I have a '68 Camaro that was rear-ended about 13 years ago and the rear panel where the tailights are was replaced. I recently went to buy an original style basic repro gas cap and discovered that it's curved opposite of the rear panel. What's going on? I was told the caps are all like that, but if so, then is my rear panel incorrectly curved? The rear panel curves like this- ) and the gas cap curves like this- (