I received a response from the seller regarding the BB nut & bolt assembly. The response is posted on the listing so I feel safe in quoting it below:
"Hi, I was told by the previous owner the bolt assembly you see under the bottom bracket was custom made for him in Rome in the late 70's the frame did not have any damage to the bottom bracket, it was simply remodified for him to remove the bottom bracket faster for cleaning and be repacked with grease. It truely is amazing! He also mentioned he was the original owner and had ridden long trips around Europe. Pictures were shown to me from Italy, Spain, Germany, Holland, France and other countries. I asked him if I could post the pictures up but he refused. Hope this helps. Thanks!"
Carlos Ovalle
Long Beach, California, USA