Check out Tony’s Parts web page, he is about to release a reproduction of these.
There are a couple of people that restore them. Go on e-bay and look up the piece, they run an e-bay ad showing before and after. Basically they repaint the back and polish the front.
There is another way...your colors on the back look OK in the picture, nothing that an overspray of black on the back wouldn’t fix. I don’t see any cracks or missing chunks that will show with the trim installed. The front is just plastic and can be polished with a progressively fine grade polishing compound (like they use to restore headlight lense clarity on new cars). I did this on mine and was surprised how good they came out.
View attachment 781850