Here's some pictures of the original finish. Pretty sure these were clear coated, however, there might be another option:
http://www.67-72chevytrucks.com/vboa...d.php?t=268199
Seems to me once blasted and polished they're back to their former glory, pending a clear finish.
EDIT: Just dawned on me aircraft paint remover might be a good option to take the paint off prior to blasting the unit, it
s pretty thick in places. Thought it might damage the plastic, but why would it? Think I've read oven cleaner removes paint from plastic, but don't quote me on it.