Hi Carl, sorry but the powdercoating company you mention don't sound very good or knowledgeable, they don't need to know if they are already powdercoated or painted for a quote as they will be stripping it off anyway if they do it correctly.
They should also be able to take in your whole car, strip the wheels and then the tyres off and strip the old coating and then spray the wheels and then refit all in 1 day, I know, I had it done last year, I had my standard smart alloys that were in silver, powdercoated black, and they look fantastic, and they are so much easier to clean with just a soft sponge.
I know you are in America and I am in Britain, but if you need any questions about powdercoating answered look at this British company where I went, their site is very informative and takes you through the whole process from start to finish.
Good luck with the powdercoating.
Ellis.
Alloy Wheel Refurbishment | Refurbish Alloy Wheels | Refurbish Wheels | Alloywheel Repair | Refurbished Alloy Wheels
I was so pleased with the finish and job they did, I sent them a piccy of the car and a testimonial, so if you go to the testimonials & gallery section, you can see my car, the blue/black smart roadster with the black alloys.