I wonder how far they would ship a new truck in the '40's and '50's. When I was living in Denver in 1975-1976 I ordered a new K20, it was built in Flint, I think it was only 6 weeks from order date to when I picked it up at the dealer. I owned and drove it for 18 1/2 years.
GM probably had particular destination limits for each regional plant. The plants are more centralized now, and stuff gets shipped all over from the one or two assembly plants, depending on model.
My '51 was built in Oakland, the closest plant to Alaska, and has stayed here for it's entire life. On the other hand, in the Lower 48, there's no telling how far a truck would be from it's home plant over 70 or so years of ownership. For instance, in 1939 my Mom's family moved from Nebraska to California with an old truck and a Model A Sedan. I'm sure that Model A stayed in California.