On C1 frames, VIN #'s were stamped on the drivers side, just across from the "X" frame
57 Chassis' were built/stamped at the A.O. Smith plant in Wisconsin
The VIN# should be in the approx. location of this pad.
Nothing there??
Starting to show up...
There it is! And it matches the VIN. ; )
A close-up of the last digit...a "2"
The VIN plate inside the driver-side door