You need to test some trim with a magnet. I think you'll find a lot of stainless is magnetic. Not all, there are different versions of stainless, but, many of them are attracted by a magnet. I believe the top quarter and belt moldings are, as well as some of the later windshield and back glass trim. So is the divider stainless between the door glass and quarter glass as well as the vent frame stainless. IIRC, the drip rail stainless is also magnetic. What I'm getting at is, if it's attracted to a magnet, it's not aluminum. That doesn't mean that all metals not attracted by a magnet are aluminum.