Hi Mignon. I don't really have a theory of my own about that, but I can point to one from an earlier thread from July, 2004: A GF II Question That\'s been Killing Me . (Link provided by plawrence in another recent topic).

First, some people noted that Rocco didn't actually make that comment; one of the other buttonmen did. (I checked the script on J Geoff's site and that is indeed the case.)

Second, dontomasso posted that the buttonman employed the deductive reasoning often found in Sherlock Holmes stories: " ... by observing clothing, haircuts, etc., you can tell a lot about someone. Their hats, shoes, etc., may have easily led a careful and intelligent observer to decude where these would be assassins came from."

That sounds reasonable. The witnesses (Michael, Tom, Rocco, etc.) probably recognized this too, or else one of them would have remarked, "What makes you think that?" Also, if that button man did recognize the dead gunmen AND he was in on the plot to kill Michael, he would have kept his mouth shut and not revealed any opinion on their origins or identity.

It was just a passing observation and we're not meant to infer any further significance from it. At least that's what I think ... until someone sways me with a better argument otherwise.