I glanced at that pic on my phone and read rivet. It is not a rivet at all and is part of the chromed pot metal surround. If the surround must be removed from the housing for re-chrome then the only choice is to grind or cut the peened heads off. Epoxy will be needed on re-assembly.
I was however thinking of the rivets that hold the inner trim to the housings. These are just tubular rivets and are easy to replace and used in multiple location's on our A-body's.
