Painting Wheel Vintiques rallyes

Hey guys:

I finally have a full set of 15" WV rallyes...my brother sold me two and I just bought 2 new ones.

The powdercoating on the new pair looks very close to what I want, which is the factory argent silver. However, the older pair have a distinctly darker, more gray powdercoating which is rusting in a few small places.

I already have the proper shade of paint on hand so I would like to repaint the wheels before having new tires mounted. Are there any specific instructions regarding painting over this powdercoated finish?

Thanks,

Tyler