Remmi

First time posting here. I have a 91 red with gray interior ZR-1 that I recently sent in for some performance work. Top end port and polish, water delete, new short throw shifter, headers, and new exhaust. When the car went into the shop it wasn't missing any paint on the license plate deck, but when it was dropped back off to me it had paint chipping and peeling off (pics attached). Car was at the shop about 6 months and the shop owner says no one and nothing banged into it. I am the third owner and I know the second owner well. When the second owner bought it it had 1600 miles on it. It has 29k miles, and there is no record of it being hit in the rear end that I can find and it has not been repainted to my knowledge. There is spider webbing in the paint in the area around where the paint is flaking off.
1.) Does anyone know what might be causing this? Is it normal based on flexing for a 27 year old C4 bumper and paint job?
2.) The only color underneath the paint that has flaked off is the black bumper material. Does anyone know what base color NOS bumpers would be--black or something else? Would reproductions be base black?
Just trying to solve the mystery as to how it had paint and now paint is missing. I was surprised to learn the paint was gone by walking around the car myself after it was delivered and not from the shop prior to delivery, but I don't want to rush to judgment. I also don't want to be hard on him if it was something that was about to happen anyway even though I have no way of knowing whether it was going to happen or not. He has offered to touch it up, but I don't know what that means exactly or what I can expect it will look like. He has warned that it will probably keep peeling even after touch up though. Any thoughts out there?

G8nightman

That looks like an impact looks at the webbing.

Z51JEFF

The bumper is black under the paint,there is a slim chance it was damaged before you dropped it off,not what you want to hear but it is a possibility and as stated something hit the bumper. The only way to fix it is to have the bumper repainted.

randy ransome

It does look like impact cracks around where the paint is missing. If that is the case the bumper needs to be stripped and repainted. Yes the bumper is black SMC under the paint. There's no way to "touch it up" and be satisfied.

Good Luck