If the zips come in undetected, not knowing the person they are supposed to kill then Where did Henry Hill's character in Goodfellas make certainly clear that when somebody was gonna get wacked, there would be a sit down and it would come from your FRIEND and not your enemy. (besides this is well known mafia fact anyway). The first def. of zip just doesn't make sense if this is the true case which I think it is.
Don't take that too literal.Its just a movie...
Most of the guys in Goodfellas were street guys,'associates',on the lowest level of mob hierarchy.It makes sense that if one of them needs to go,they would have someone close to him do it.That's the way it is most of the time.It happens that way because someone like say Henry Hill isn't important enough to warrant having an experienced hitman(from the family or from Italy) do him.
It should be pretty clear that if someone wanted to kill someone important,like say John Gotti,they would not go to Gravano and tell him to do it.
