I seriously doubt it was either of them. I'm hearing that he had taken to dealing directly with some young Black and Latino gangsta types, and that it was probably a spur of the moment drug deal gone bad. I can see it because the guy didn't have two nickels to rub together towards the end, and he was desperate to earn.

Matty and Nose both have too much to lose to hit a complete scumbag who hasn't been relevant this century. Matty has other cases that he's trying to get concurrent time on, and Nose has his hands full elsewhere. Plus, neither of them would have liked the idea of the hit going down where it did.

Mickey Meldish still had a small rent controlled studio on Second Avenue around 109th. If it was an old time mob guy, in my opinion that's where they hit him, in Harlem, for the irony, history and significance of it all.