Yours was probably a model 71 Jerry. Pictures below swiped from an eBay add, but may be interesting for someone.
1st picture is of a "government #71". 2nd picture is the back of the same ratchet, showing the date code near the "on/off" selector. 3rd picture is the magic decoder ring for Snap On date codes.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.