[Uncle Bob]

Well David, I had thought you might dazzle me with some nugget that this was a rare early production idea that faded away. Your comment about the rolled lip, and my need to do other further inspection underneath, caused me to look at it from another angle. Pic below, my guess now is that it was center punched on an obstruction of some sort down very low with minimal damage to the rolled lip, but looking at the gap to the pad that separates the the bottom of the rad shell the "bubble" is the result of the shield being bent back. It's only about an inch from the axle. The side buckles though are so uniform it's uncanny.................really looks like a stamping outcome.

I will say there is some beauty to the underside of the of this car. No evidence of repair and the frame rails have absolutely no pitting wherever accessible. I'm not going to remove anything that would allow inspection under the webbing where there must be some deterioration, but for what can be accessed it's really nice.