[PropellerHead]

Those look like machine tool marks.
When you sanded, what # paper did you use? Hand or machine sanding? Wet or dry?
When I refinished my Fuchs wheels I stripped the paint, then the anodizing (used Easy-Off Heavy Duty oven cleaner for localized removal) before sanding and polishing. I used a sodium hydroxide bath to remove the black anodizing from the center caps and it worked like a charm. I didn't mix up a large enough bath to do complete wheel faces, that's where the Easy-Off came in (same chemical in a spray can!). It leaves a nice even etched aluminum which is relatively easy to sand and polish.
I imagine the aftermarket Fuchs styled wheels are also protected with a clear anodized finish but I can't be certain. If it does indeed, you'll need to remove it via chemical or mechanical (sanding) means to get a good polished finish. It is difficult to remove mechanically as it is a very hard surface.