101 22 P 24831

10 ...................... is 1/2 ton
...1 .................... is short wheelbase
.....22 ................. is 228 cubic inch engine (the only one available)
........ P ............... is manufactured at the Pontiac Michigan plant
........... 24831 ...... is the 23831st truck built. The first one was 1001

Additional info can be found here along with the year decode based on the serial number 24831.

'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.