I dunno what kind of finish is on them. They came with the car. To be 100% honest I was going to sand them down to paint them gold. But I had some very fine grit sandpaper left from a previous project so I just used copious amounts of soapy water, some very gentle rubbing with the sand paper and about 45 minutes a wheel for that process. I used mothers wheel polish for the passenger side, ran out of time to polish the other 2 but they still look almost as good as the 2 polished ones.
I am still on the fence about painting them. If I can get them to look even nicer than they do now I may just maintain them and keep em clean the way they are.