In my experience the AD trucks used castellated nuts and cotter pins to hold steering arms on. I remember because the cotter pins are difficult to remove after half rusting away.
To know for sure the parts book might explain.

In the late 80's and into the 90's on a a GM straight axle the steering arms bolts have a heavy SAE washer and self locking all steel nuts.

•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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