Here is a copy of the serial number explanation from the manual. I have the same page in my manual for 1948 to 52.
old GMC Trucks . Your truck would be all Chev mechanically. Even the white on brown instruments are in Chev colours. Most cartalogs have listings using the US series numbers so I believe yours would be a 3100 in the catalog. I am curious which motor you have. I have the Canadian 216 with the short side cover.
