I recently received an email from my old friend, mentor, and Ford 8N Tractor innovator extraordinaire Marvin Baumann. I have never seen anything like this before. The "GP" prefix could likely be in reference to the Ford GPW vehicle (JEEP) but why designate a 9N with it? I don't have any more details and am arranging to go see this in person and take numerous photos.
Marvin writes:
Tim
I ran across this all original 9-N today {GP8923 serial number) in excellent condition that a friend just purchased. Evidently it may have been government owned with the Fort Knox tag {Attached to block} on it. I did not understand the “GP” designation on the serial number for a standard tractor, Marv.
-Tim Daley(MI)