[RenoKeene]

Here is the whole GMC VIN CE134-SZ58131
I believe the prefix (S) is the mfg plant...St Louis
C=2WD
E=V8
1=1/2 TON
34=FLEETSIDE
S=ST LOUIS
Z=1970
58131= 8131st truck built

So.....GMC only stamped the Plant and the build number?

This truck seems to have been an oddball anyway....1/2 ton FACTORY BIG BLOCK A/C 6 lug CST 127", with aux fuel tank switch in the floor (exactly the same as my 72 Custom Camper). The tank was gone but the mounts were still there, this is where it gets strange...the hangers for a tool stowage box were still mounted to the bed floor but that bedside had been replaced. Leads me to believe it was a Custom Camper but there were only 3 holes in the door above the door handle for the Custom emblem, no Camper emblem.
Did they even make a 1/2 ton Custom Camper?
BTW instead of a SPID I got a chrome glovebox door.