Just for giggles I tried a little experiment on the Parts Place reproduction fat wheel I bought last year off of ebay. While it is dimensionally correct version of the early "fat wheel," the makers used a hard plastic-like, urethane with an incorrect heavy grain and fake mold seams on it.
I used the orbital sandle with 220 grit and sanded the edges more round where they meet the spokes and partially sanded down/smoothed the entire rim and especially the fake seam they had molded into the outer circumference of the wheel. I then sprayed it with several layers of the Plasti Dip spray. I think that is the trick for the repro wheel if you wanted to use one of these for your GTO or T/A. It really got rid of the plastic repro look and now looks like the original black foam.
I might install this wheel as my primary wheel and use the original one for shows (in the event I ever finish this confounded, eternal project)