Glad to provide what help I can and that you were able to get things remeasured and confirmed your wheel base measurement as 115".
I have original copies of both those shop manuals and can confirm first that the text in those does
not specify the wheel base length in either, while it does show for all other trucks 3/4 ton and up.
Definitely odd! Also confirms both 1/2 ton truck frame Shop Manual drawings show the 44-1/2" rear frame width, which I think is an error (I agree they have made them).
Your remeasured 115" wheel base matches the 115" wheel base specifications for 1941, 1942 and 1946 1/2 ton's in the GM Heritage Center archive data files. All three of those documents also specify the rear frame width measurement to be 46" across the widest surfaces (not the 44-1/4" in the Shop Manuals). I think I trust the data in the Heritage files for accuracy more than the Shop Manuals, so I think you can safely say your frame is of the '41-'46 variety.
Anyhow, moving on, have you attempted fitting up a rear bumper to your frame?
