By now everyone has heard Ben Silverman's soggy rationale for reintroducing 30 Rock so late in the fall season — everyone except Tina Fey, it appears, whose sit-down today with the Associated Press revealed that she doesn't know when or even if she will revive her recurring Sarah Palin gig on Saturday Night Live. An NBC spokesperson corroborated the network's uncertainty. Who to believe?Of course, that's not an especially fair question to ask any time Silverman's in the equation. But after his admitted miscalculation in scheduling three primetime SNL specials in place of Fey's eagerly awaited Emmy incumbent, he corrected hard with his insistence in Sunday's New York Times that "she would surely be on the next two SNL specials 'heavily promoting 30 Rock." But if we're to take Fey at her word, she and the SNL braintrust have yet to receive that memo: