exterior trim

Can someone tell me what the trim is made of?I was cleaning some trim here the other night and realized with a magnet that the window trim that I thought was stainless can't be stainless because its magnetic.So when that happened I checked a bunch of trim I had in my playroom from a 70 Challenger and a bunch of 71 Cuda trim and all the thin trim for the 71 Cuda grille,back window corners was magnetic and the only pieces that were not magnetic were the 2 SE pieces from the top/back of the Challenger fenders.