UPDATE: DRAFT … I NEVER FINISHED THIS POST
Here’s the most complete information on 4 Wheel Steering that I could find. I found it at JeepStation.com (http://jeepstation.com/main/?q=node/18). Looks like Ford built 100, Willys 50 and Bantam 50. If anyone knows more, please add info. This is likely a GPW-4WS.
BRC-40-4WS: American Bantam Jeep, 4 Wheel Steering – 50 built. (62 according to this site)
MA-4WS: Willys Military model A with 4 Wheel Steering – 50 built.
GP-4WS: Ford First model Military with 4 Wheel Steering – 50 built.
GPW-4WS: Ford Military 80″ wheelbase, Willys design with 4 Wheel Steering – 50 built.