When I registered my M725 they could never figure out how to put the hood numbers as the registration number. They used my VIN # as the registration number. It took several hours to get it done. I got tired of messing with it and accepted the VIN# and left. I went ahead and placed the sticker on the windshield to keep from loosing it. When I did my M35 I got a hard plate as I have not put numbers on the truck yet. I am waiting on doing the paint first and then will redo it with the hood numbers, maybe if they can figure it out.
Good advice would be to keep a copy of the law relating to the former military registration and inspection in the truck with you incase it is ever questioned.