Hi,

Yeah Rustoleum and Resin is a no no. Kind of the same way Vinyl does.  Not sure of the chemical why and what for, but if it does "cure" later it will form cracks and blister.   Works great on styrene and metal just not on resin.  You can safely strip it with no damage to the resin.  You can first spray an Adhesion Promotor (found at auto parts stores) on first and then prime with Rustoleum with no problems.

Hope that helps

Steve