I would like to mention so as to widen your net not to dismiss a otherwise acceptable rechromed or unrestored core bumper because of straightening marks on the back side. Those marks can be convincingly covered up after the fact (restoration of the bumper) with bodywork (bondo etc.) and covered with one of the chrome like paints. If there is rust on the back side careful blasting to remove rust and scale and then do bodywork to remove pits. Of course it is best to have a virgin backside but not all of us are that lucky to find that. A well executed bodywork and paint job on the back side typically does not stand out as unusual even in trailered concours.
