My friend and I drove up to Chrysler Proving grounds for what I think was the Mopar Nationals in 1982. I had my early 70 Challenger R/T and he had his 70-1/2 Challenger T/A. As I was looking at our cars side by side, I noticed his front fenders bulged out at the body line, to make the fender WIDER at the wheel wells, where mine didn't bulge at all. I always figured that this was the 15" wheel fenders. It's easy to spot after seeing the 1st one.
Rob