Those plastic rivets which hold the painted top-piece are a little pesky to remove. I found alternative trim panel retainers at Autozone that work better IMO. They are GM 458780, and press into position. Fit is good, required moderate force to press into position, and they don't seem like they will easily dislodge. The heads are slightly larger, and you can carefully slide a thin pry tool underneath them to get them started and then a larger tool to pop them out if needed in the future. Here are a few pics below of the new pins, the old pins, and the new pins installed.
Threaded Mode
