The "cookie cutter" rims were made by ATS and they were cast, not forged, so the surface finish is not as smooth as the Fuchs.

I don't think I've ever seen any "original silver finish" OEM cookies from 1973 (weren't they all 6" rims that year?), I have only seen black centers with a polished lip. If you're trying to paint them, they will probably need several coats of a hi-build epoxy primer with 180-grit sanding to smooth out the porosity before the final color coat. I would consider powder coating them, as the electrostatic coating does a good job of filling surface imperfections, and there is a wide range of colors available.