1964's were red, had a taillight mounted to the rear fender strap, and used 6" 3 piece steel wheels. for 1965 the bikes were changed to blue, the tail light mount point was raised up to the frame and Gran Prix wheels were introduced. I would not doubt there are some other little things as well but those were the majors. Go to the USminibikemuseum.com and dig through the Rupp section, they have some of the info scanned from old magazines posted up.