71 GMC VIN # Is this right?

[TreverSlyFox]

Just bought a 1971 GMC 1 Ton. The Vin Plate on the door post and the model decal on the glove box door match:

Vin Plate on door: CE303S11XXXX (rivets are original)

Model Decal: CE36003 (also gives the VIN as CE303S11XXXX) and states the wheel base as 133" which it is.


Title gives the VIN as CE303S11XXXX and 1971 GMC TRK

Here's the question: What gives with the VIN here? The 5th digit is the year code and should be a "1" (maybe a 0 if it was a 1970 sold in 1971) NOT a "3". Also the 4th digit is the model code so what is a "0" the code for? I don't find a "0" as a model code anywhere.

Where is the "hidden" VIN location on the frame? I'ed like to see if they match.