The plate is also held on with some sort of adhesive, you may have a hard time getting it off in nice shape.
I'd say just have them mask it off with some tape that will survive the heat.
The correct rivets are available, if you run a search for the terms vin plate rivets, you'll find a few members here who have bought the minimum quantity from a vendor and have about 98 rivets to spare, a few have offered to mail them out for low cost.
good luck.
-Alan