Lon:
Talking about Opel? Remember the OPEL-GT? We had one in the shop that was my paint mule (The front was toast!). One Day I got a bug, you know where! I pulled it out of the Bay adjacent to the Paint Booth. I cut it back to the Firewall. Found another that an 18 wheeler removed the back from!
Put them Both together and when she was done, I kept her for my advertising vehicle. I learned that little trick from my Police department jobs! The whole trick was locating a spot that helped Hide the welds and doublers. If it had a frame we usually bought an intact frame from The salvage yard. So Fords and G.M. makes got new frames if the bodies were Joiner Jobs!
Unlike Models where you can use a ruler on, I had to have a Frame Jig and Alignment machine. If It didn't meet optimal Measurements It was stripped! Those were how my guys were taught the trick. Some got so good they left me for the dealer shops. I paid better, but, they wanted the Attention I guess!