Nils, I realize you are excited and happy to have this wonderful truck. So far all of your post are obsessed with the exact lineage info. Your truck's exact born date and history will take a lot of research by you. Not us. We have already done a lot of research for you, cyphered your VIN, pointed you to the tip section and some very knowledgeable members have given their opinions. Much of what you are asking is simply unknowable because of the age, the war interruption era it's from and your Chassis No. not being kosher.
Do you ever plan on working on the truck to get it in shape? We will know everything about that phase. What condition is it in and what are your plans?
I hope all these born on/history questions are not just to be able to sell it as something special and use this site as support/proof. It's starting to feel like that. All of your 7 posts, in two threads, are about the same issues. I think you are at the end of this phase. Further discussion is blogging.
As a new guy, we have respected you and have given all we got. Our willingness to help has made us responsible for this long discussion. Not your fault. However: You are in the General Talk forum which is defined by the editor as "related to the care, restoration, preservation or use of old GM trucks! Off-Topic discussions go in the Greasy Spoon Forum!" You are mission creeping out of that definition.
Your other thread was in the welcome center where you introduce yourself and your truck. You did that very well, but it turned into a VIN decode discussion also.