Thanks for all of your input. A local Mopar guy, one of the firefighters I work with, also added the recommendation of having the panels media blasted by someone with experience with plastics. Most of the crud is in the grain. I have in the past used a tooth brush to clean the grain out without damaging it.
The plan is to dye black panels to brite blue. These panels are mechanically in sound shape. Lots of cleaning with lots of soap followed by SEM cleaner to clean off the soap, followed by SEM adhesion promoter. Then the paint will go on.
Craig