There is a scene that was actually filmed, but never included in any version (not even as a deleted scene anywhere) in which Michael, dressed in classic gangster clothes (pearl-gray fedora, black coat) walks into Fab's pizza place with Fab's own lupara, and blows him away. You can see stills of this scene in Harlan Lebo's "The Godfather Legacy," pp. 180, 184-5, and 200. What I wouldn't give to see that scene!