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.
Attachments
SnapOn71.jpg (123.61 KB, 118 downloads)
SnapOn71Back.jpg (63.87 KB, 119 downloads)
SnapOn Date Codes.jpg (49.11 KB, 121 downloads)


'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.