In this documentary at around 1:03:18, Billy Beattie says that there was the plan for them to kill Castellano etc if something went wrong. But the group that was supposed to have done the killing were all sitting around off their face on drugs.
https://www.youtube.com/watch?v=VN_oO4gkIWUThat's true, thanks for pointing out (I had this documentary for some time but still hadn't watched)! Really, I have no words....Assholes, those Westie "soldiers"...And I really thought they were about to behead 2 strongest Mafia families in the USA and just missed the chance. As it seems, far from "beheading" the mob, they probably wouldn't be able to stick their heads right under the guillotine if they were to be beheaded themselves (well, maybe the allegory is a little clumsy, but this is the only think I could think about).
The "Mobsters" episode "conveniently" omitted this detail as I remember.