It's hard to believe that they didn't know shit when they contacted Pac and coordinated the studio session with him to make sure he arrived to do a track.
Since the Bad Boy crew was there at the studio and setting up the session, who else but those guys could have told the people robbing Pac that Pac was coming? Either they told the guys who robbed Pac that he was coming, or the Black Mafia guys just happened to be sitting in Quad late at night waiting to stick up someone and it was just Pac by chance.
Considering the guys who set him up had financial ties with Bad Boy, and Tut admitted to an informant that he set Pac up, it stretches the imagination to assume that nobody in Bad Boy knew what was going on that night.