17" multi piece rims are normal and original on AD single wheel 1 tons.
I've not seen an old 17" tubeless wheel. (not to be confused with the new tubeless 17" wheels on newer cars and trucks)

I expect those wheels you have that appear to be tubeless in fact are, but are really 17.5" wheels. They are somewhat desirable, I've seen them sell and even sold some for more than I thought they were worth.

I prefer 19.5" wheels though, they are tubeless too and look about the right size on the 1 tons.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-