Not OP, but since I looked up the corresponding UK process: https://www.gov.uk/vehicle-approval/individual-vehicle-appro...

You end up with a special "Q" (as in James Bond?) number plate. There's a whole bunch of different processes depending on how Car of Theseus the vehicle is. Apparently this has recently been streamlined for rebuilds of classics from original parts (which is _not_ what the Jeep is). The system is still intended to prevent the re-use of crashed or otherwise written off frames, though.