1320,
I gave you wrong info, I got things out of order because the book was kind of confusing. I found this out after reading the models of other years.
'39 1 1/2 Ton Model VA & VB were were 133' WB single and dual rear wheels. VC & VD were 158" WB single and dual rear wheels.
I also found a picture of a single rear wheel 1 1/2T and, unlike the early models, it has the same wheels as the dual. It is just turned in like the front, as you said. This would make a pretty narrow tread for the rear, but it is right there in the picture. Duals sure look a lot better.
I just finished installing a new flap and tube in my inside tire and found that the split ring is quite a bit different than newer trucks. It was actually pretty easy to remove once I discovered the right way to release it. It doesn't require a special hooked tool like newer ones.