The seat mount is quite different than later bikes. It is made out of C channel steel and is welded to the rear fork stays since there are no braces going up to the rear rack. Rear stays are also missing on the #2, #3, #4 and patent bikes. They are probably also missing on the #1 bike but the picture is not clear enough to tell. The spring mounts are moved outboard compared to later bikes. The front mounts are 3/8-24 UNF nuts just like the later bikes.