reworking a fully restored car

Granted, I'm no career body man. But when I asked my paint supplier his answer was a modern urethane clear can be sprayed over almost anything. So give it time to fully cure (I use a month of warm storage), "make it smooth", and then shoot it. Unless the top coat was dusted on it, the metallic should not change. If you wet sand down a couple layers - that's another story. But peal shouldn't be that deep. As I said - the cars I've done that on have been through some hell and the finish is still there and no separation.