On the 02 V11 sport I had, I am pretty sure the wheels were painted. If it was powder coating, it sure was weak, and would scratch easily. I had the charcoal grey color matched by the computer/camera at my local automotive paint store, and it was very very close, except that the OG had a satin finish, and I sprayed them with a gloss clear over the base coat. I could have done a satin clear ,but used what clear I already had on hand.
I used DuPont Chromabase to get an accurate color match, and the wheels came out better looking than factory IMHO.
That was when I invested in tire mounting equipment, and started doing my own tires, after having a couple of different shops nick my wheels.