71 ‘Cuda fenders, original, or reproductions?

I recently purchased some 71 gilled 'Cuda fenders. It appears at one point that they were media blasted, or acid dipped and stored with no primer/paint on them. The are not rotted or scaly, surface rust is my concern. since these have rust, I cannot see any "stenciled" part numbers on them, is there some stampings somewhere on the inner fender parts, so that I can tell if they are original 71 parts? If so, can you tell me exactly where to look for these numbers? Thanks much in advance.
Author: FFGREG