I have no experience with repo mopar sheet metal, but I once bought a 67 mustang project that came with two reproduction front fenders. They were paper thin and they didn't match the profile of the leading door edge either. I could not justify putting a nice paint job over something like that so I sold them and went with a nice set of ford originals.

My brother used Goodmark sheetmetal when he redid his oldsmobile cutlass and everything fit pretty nice. They charge a little more, but you don't hear a lot of complaints about their product.