Its the Genovese, nobody really knows who the real boss was. But Tieri was said to be an official boss until he got sick and died. Lombardo was always said to have been aprt of the panel at some point with Eboli & Tierei. After Tieri passed Lombardo was officially made boss, again thats according to most sources. Either way there's no room for Bufalino ever being an acting boss for the Genovese.