All, need input. 1985 fiberglass 40 foot motorcoach. Not sure what paint/clear was on it. The owners book said acrylic urethane. I think camper was repainted/cleared at some point but not sure. I rubbed a spot with lacquer thinner and got no reaction. In fact, the lacquer thinner seemed to bring the color out. I want to paint with lacquer paint/clear but concerned if it is still original acrylic urethane. How can I tell for sure? Thank you so much for any advice.