Many years ago my brother purchased a small fishing boat for me in Oregon where he lived.
I met him halfway driving time, paid him, then took the boat home to Utah, and it did not need a trailer plate at that time due to it's small size.
Upon retiring, I moved to Montana and the boat trailer needed a trailer plate, and being it was home a made trailer it was lacking a serial number.
DMV required me to get a statement from my brother saying the trailer was home made, then DMV assigned the trailer a serial number.
I purchased a metal stamp letter/number die set and stamped the serial number in the tongue of the trailer.
Then I had to get a LEO to view the serial number on the trailer and sign off the DMV form to get the Montana trailer plate.
The hardest part was stamping the serial number, trying to make it look sort of good...
KC
The trailer serial number DMV assigned was SNTR00000MT (except it was not 5 zero's).