Not to be outdone by Artie, Dominick Montiglio estimated 500-700 in one interview. No joke.
Wow. Was he drunk or high or something?
A lot of law enforcement types do this - exaggerate the significance of the mobsters they are up against,
even if the reality of the mobsters is that they were deadly, powerful, and require no exaggeration to sound formidable. Bill Roemer was pretty bad about it. So is Pistone, with his insistence that there's still an open bounty on his head.
This is one of the weirder phenomena in the history of law enforcement vs organized crime. I call it "gangster inflation". It is very, very silly.