When I bought my car one of the rivets was barely hanging in the hole, and I salvaged it and reused it, then refilled with bondo and painted it. So, the trim tag rivets can be saved and it will be unnoticable if you don't molest the firewall side of the rivet head. They are basically brass grommets filled with bondo and then painted over. From the windshield side of the firewall with the cowl panel removed, dig the bondo out of the inner edge of the rivets, enough that the bondo plug can be pushed through toward the engine compartment. Once the filler is out, then carefully bend the brass grommet edges inward with an ice-pick or very fine nose pliers, so that this brass rivet/grommet can be pushed toward the engine compartment.