[Stew Masche]

Check with your State Historical Society if they may have past DMV records. The Wisconsin State Historical Society has Wisconsin DMV records from 1905 to 1948 or so for trucks, and 1905 into the 50’s for autos, also motorcycles.
A few years ago, I managed to find out who the original owner of our AA truck was, after searching the records for 10 hours, searching by the serial number. Good Luck !