Will he? Will HE? Why he will do it: --AGT premieres on Monday. --Howard owes Lorne Michaels a favor for allowing lowly Stern lackeys to interview him for "SNL on Stern." --The last time Will Ferrell hosted SNL, three years ago, Artie made a cameo. Why he won't do it: --He'll have do the dress rehearsal (at 9:15 pm) and the actual broadcast (airing at 12:15 or 12:30 am), which is too late for Howard. When does he ever go out past midnight? And if he's out too late, he'll be too exhausted for Monday's show.