Thanks - Might consider putting that in your signature
So don't have access to a unrestored 70 Dearborn car this moment and of course, if we don't have to, would rather not rely on a single source. Ribbing, at least on one surface may, like rubber hoses, identify the supplier of the bumpers.
Not the best pictures, since that was not the focus of the picture taking, but should provide you some clues
As for profile of these bumpers (wide verse thinner) not sure if I'm seeing an unbalance in these originals though we accept that under the pressure from the hood sometimes they can take on different shapes when compared to uninstalled originals. Some more pictures in addition to the ones included above
Hope this helps