Hi Chuck,
I painted my race bike's frame and swing arm and what I have learn is that it doesn't last very long, small stone chips everywhere and it does scratch easily.
The reason I went for paint is because powdercoat weighs a ton and when it chips it is really deep. Originally I wanted to anodize it but there is a 50/50% chance that it might not work on the cast bits. When it doesn't work then you end up with a green looking piece of metal which gives off a green "dust" every time you touch it.
Its all to do with the % silicone inside the metal, some manufacturers use very low % of silicone( Eg. Honda ) and some use a lot. BUT there is no guarantee that it will work, you have to try before you know. Even one frame of the same model bike will work and then the next wont...
If I could give you some advise, try to get it cleaned with vapor blasting and then treat the metal with something for oxidation. I dont know if clear coat over it will be the answer....
Cheers
Mario