Well, first they can't be rotted. If you can run your finger nail over it and the plastic comes off under you nail, it is rotten. For small nicks and so forth you cam make a kind of flexible mold of the pattern out of RTV, or some non harding agent. something like silly putty. Kind of hard to explain what I'm talking about, but something that will retain the pattern, then with some heat that will just soften up the bad spots, press the putty so it can reestablish the pattern. When you get it as good as you can, lightly spray with vinyl die, or rattle can paint just to get a little color and some gloss. I don't mean paint it, just mist it. That is the best I can explain it. BUT, they can't be rotted
Vacuum formed just look cheap and crapy, the grain is to big and cheap looking, the stitching pattern that goes around the edge, if I remember correctly is missing. They are just cheap looking. Chrysler spent a lot of money on injection molds to make nice looking parts.