You are going to have to properly strip those parts when it comes time to paint. Autopaint and Rustpaint don't jive well. You'd be better off getting some generic white spraybombs from an auto-paint store (NAPA?) and saving yourself the hassle later of sanding the rustoleum off (you can't use aircraft strippers nono )CallMeMud:
Good ole Rustoleum! Just want to make them match until I get the whole car painted beginning of next year but didn't want all the paint to come off the first time I wash it nono headbang