As a connoisseur of pissing matches large and small, David Mamet must be amused by the offstage drama that surrounds the two dueling Mamet revivals opening on Broadway this fall.

Producers of the two shows — “Speed-the-Plow,” which opens October 23, and “American Buffalo,” which opens November 17 — both went after the same theater, the Ethel Barrymore on West 47th Street, after it was made available by the cancellation of “Godspell.” When “American Buffalo” lost out, the New York Post described one of the producers, Ben Sprecher, as worrying that he looked “weak.”

Meanwhile, the lead producer of “Speed-the-Plow,” Jeffrey Richards, doesn’t hesitate to say that he thinks his production is more timely. “‘American Buffalo’ is a very fine play, [but] it’s been done more frequently,” he said. “I think ‘Speed-the-Plow’ is more unexpected.”

But in fact, the coincidence, while an annoyance to the producers, is a boon to New York audiences, giving them the chance to compare one of Mr. Mamet’s earliest plays, “American Buffalo,” produced when he was only 27, with a work written when he was already an established presence on Broadway and had begun working in Hollywood. The two plays have similar themes — above all, loyalty and betrayal — but are set within different worlds: “American Buffalo” among the small-time hustlers in a junk shop in Chicago, “Speed-the-Plow” among the slick, big-money hustlers of Hollywood.

In “American Buffalo,” Don, the proprietor of the junk shop, and his friend Teach plan a theft, which Don’s protégé and gopher, Bobby, has scoped out. In “Speed-the-Plow,” Charlie Fox comes to his old friend Bobby Gould, who has just been promoted to a big studio job, with a trashy script for a buddy movie with a big star attached. Meanwhile, Gould’s fresh-faced and idealistic temp assistant, Karen, wants him to green-light a movie based on a highbrow but (as far as we can tell from the parts we hear) largely incomprehensible novel about the world ending in environmental disaster.

“They’re kind of the same play in a way,” Gregory Mosher, who directed the first production of “American Buffalo,” at the Goodman Theatre in Chicago in 1975, said. Mr. Mosher also directed the original Broadway production of “Speed-the-Plow” (which starred Madonna as Karen) in 1988. “There’s a guy who wants to do well. There’s a guy who doesn’t want to do well, who wants to look out for himself. And there’s a person who’s caught in the middle. It’s a kid in ‘American Buffalo’; it’s a young woman in ‘Speed-the-Plow.'”

The plays are tonally different, he added: “‘Speed-the-Plow’ ends up as a comedy, [whereas] the ending of ‘American Buffalo’ is clearly tragic.”

Both productions have what look to be stellar casts, with the requisite Hollywood celebrity quotient: “Speed-the-Plow” stars Jeremy Piven (Ari from “Entourage,” who also appeared in Neil LaBute’s “Fat Pig” at MCC Theater in 2004) as Bobby Gould, Raúl Esparza (of “The Homecoming” and “Company”) as Charlie Fox, and Elizabeth Moss (Peggy from “Mad Men”) as Karen.

The director of “American Buffalo,” Robert Falls, wanted to work with a multiracial cast, who he said “had not necessarily had opportunities to do David Mamet before.” (In the original script, the three characters are presumed to be white — although in the film version made in 1996, and produced by Mr. Mosher, a young black actor, Sean Nelson, played Bobby.)

John Leguizamo is playing Teach (the role played by Al Pacino in the 1983 Broadway production and Dustin Hoffman in the movie); the comedian Cedric the Entertainer is playing Don, and Haley Joel Osment (of “The Sixth Sense,” all grown up) is playing Bobby.

The contrast between the two plays is particularly interesting in the context of some of Mr. Mamet’s recent nonfiction writing. In March, in an essay in the Village Voice called “Why I Am No Longer a ‘Brain-Dead Liberal,'” Mr. Mamet said that he had undergone a political conversion.

As a child of the ’60s, he for many years “accepted as an article of faith that government is corrupt, that business is exploitative, and that people are generally good at heart,” he wrote in the Voice. But no longer: Now, as he declared in a recent article in the New York Times promoting “Speed-the-Plow,” he sees the free market as a brilliant mechanism for distributing cultural products:

“[I]ndividuals or corporations can be as greedy as they want, but they can grow rich only through fulfilling a need,” Mr. Mamet wrote.

As a result, commercial television and Hollywood “give us the Badda Bing, and Not That There’s Anything Wrong With That, and I’m Mad as Hell and I’m Not Going to Take It Anymore, and ‘South Park,’ and Dennis Franz, and Sarah Jessica Parker, ‘Six Feet Under,’ Nascar and ‘Lost,'” he said. “All we’ve ever had from public television is 60 years of the cheetah overpowering the same old antelope.”

Mr. Mamet’s political change of heart casts a new light on “Speed-the-Plow” and “American Buffalo,” both of which have a lot to say about the competition and the marketplace.

Mr. Falls described “American Buffalo” as a savage look at the limits of capitalism. The three characters are men “at the bottom of society, who have these pretensions of themselves,” he said. “They see themselves in the same way that Wall Street traders do: as rugged American individualists, who are taking advantage of the system. [They’re] basically criminals — but, let’s face it, aren’t some of the guys on Wall Street criminals, too?”

It’s interesting to wonder how Mr. Mamet, who was not available to be interviewed for this article, sees the two plays now. Was his article in the Times in praise of “Speed-the-Plow” a declaration of greater affinity with that play, which takes a more comic view of capitalism? Or was it a gesture of loyalty toward Mr. Richards, his own Charlie Fox, who produced the hit revival of “Glengarry Glen Ross” and then shepherded the critically panned “November”?

Asked what he thought of Mr. Mamet’s new politics, Mr. Falls said he wasn’t sure how seriously to take the conversion.

“Whether he’s writing essays or plays, his public persona is that of a provocateur,” Mr. Falls said. “He’s also sort of a con artist, he loves the con game. I never know whether what Dave is saying is the truth or not.”

One thing that’s certain, however, is that Mr. Mamet’s provocative playwriting style, which was first nurtured in Chicago’s nonprofit theater world, has ultimately been embraced and propagated and assimilated by the larger, market-driven culture.

When “American Buffalo” first opened in 1975, its explosive, expletive-packed dialogue was shocking, Mr. Mosher recalled. “The word ‘f___’ had been uttered in the theater only occasionally,” Mr. Mosher said. “When David started, that’s all people could hear.” The dean of Chicago theater critics, Claudia Cassidy, said of “American Buffalo” that “if you took the dirty words out, it would last only 20 minutes,” Mr. Mosher said.

Today, Mr. Mamet’s style is hardly shocking: It sounds like so much else that we hear on television, in the movies, and in the work of playwrights who learned from Mr. Mamet, such as Neil LaBute and Eric Bogosian.

These days, Mr. Mamet himself puts as much work into writing and directing and producing for film and television as he does into writing plays, Mr. Falls said. “Whereas in these earlier plays,” he said, referring to both “American Buffalo” and “Speed-the-Plow,” “this was his contribution to the world. He was a young artist on fire, coming out of the gate with a remarkable vision that really changed playwriting.”