Hello.

On the 65/66 cars the pieces that were structural components, like the inner fenders, radiator core support, strut rod brackets and such, were stamped in Dearborn, and the panels which were painted body color, like the fenders, hood, trunk lids, etc.. were stamped in Cleveland. The things to look for are the actual dates, and evidence of the panel having been replaced. The body panels were all spot-welded together, with the exception of the front end of the strut rod brackets. They were spot welded, but they also got a bead of ugly looking weld along the front where it overlaps the bottom of the radiator core support.

The later cars are a little more involved than that, but, the date code/ spot weld thing is still the case, except for cars that came with staggered shocks or reinforced shock towers.
So, the short version of the answer is " Yes, different panels did come from different places."
