To recast or not to recast?That’s the question for producers of Broadway play “The Mountaintop.” The show has so far eked out a single-week extension of a limited run that, at least for now, ends Jan. 22, when Samuel L. Jackson, who stars in Katori Hall’s two-hander with Angela Bassett, must exit to shoot a film. And it’s a question faced by every producer of a promising production that can attribute a major percentage of its aud-appeal to a big-name cast. Recasting always comes with B.O. risks, and for “Mountaintop,” the jury’s still out — but producers Jean Doumanian and Sonia Friedman acknowledge it’s a possibility. “It’s eminently recastable,” Friedman says of the show. “Mountaintop,” about Martin Luther King Jr. on the eve of his assassination, is one of several unusually strong-selling plays on the boards these days, but at the moment it’s the only one grappling with the idea of recasting. Last season’s Tony fave, “War Horse,” has managed to make its puppet equine the defacto star, pulling in close to $1 million per week without a Hugh Jackman to propel sales. This season’s “Relatively Speaking” is also posting solid numbers, but while there are familiar thesps in the show, the real draw seems to be its trio of big-name scribes: Woody Allen, Ethan Coen and Elaine May. Another non-tuner attracting crowds is “Other Desert Cities,” which also features some well-known actors, but seemed — at least prior to its Nov. 3 opening — to be packing houses based mostly on the buzz the show had accumulated in its well-reviewed Off Broadway stint. That leaves “Mountaintop,” which could well survive without Jackson and Bassett, thanks to the show’s link to a civil rights icon and a built-in appeal to the African-American demo that can turn out in force for the right Rialto play with the right cast, as illustrated by prior Broadway successes including “Fences” and “Cat on a Tin Roof.” Still, depending on who the new stars are, a cast change can always throw a show off its game. Box office smash “God of Carnage,” for instance, never had quite the same mojo it did with its original thesps (including James Gandolfini and Marcia Gay Harden). Besides, recasting isn’t the only option for “Mountaintop,” to hear producers tell it. The show’s starry Broadway bow has helped give the play a national profile that’s spurred interest from regional presenters. In addition, producers are talking about a live HD cinemacast of the show, probably sometime in January, with Broadway Near You, a company of which “Mountaintop” helmer Kenny Leon is a.d. There’s also the possibility that Jackson could be tempted to return to the production following his film engagement, which seems to suggest a possible scenario that might see Bassett appear in the show for several weeks with a temporary co-star. Producers wouldn’t confirm this possibility, but it’s said the play’s new TV ad is notably Bassett-centric, featuring the actress delivering the show’s memorable, climactic monologue. “We’d love to get Sam back,” Doumanian acknowledges. Hall’s script already has had an unusual trajectory, bowing in a tiny fringe theater over a London pub before jumping to an Olivier-winning West End run and its Broadway incarnation. Doumanian and Friedman, who both got involved in the play in June 2009, say they’re certain the play has plenty of life in it, but still aren’t sure whether it’s on Broadway or beyond. “We’re not done with it yet,” Friedman says.