I'll throw in a disclaimer here and say that I have no first-hand experience with AD 1-ton front spindles/hubs, but that won't stop me.
From what I can find in the truck specs (in this case, from '49, which should be the same thru '52) and the Chevy master parts catalogs, only one spindle is listed for all 1-tons (excl. Dubl-Duti), with no distinction between single or dual rear wheels. In fact, the '46-'50 3/4, 1, and 1.5-ton, and '51-'52 3/4 and 1-ton, all use the same spindle (or knuckle).
As for 1-ton front hubs, I see no mention of hub extensions or adapters for the dually trucks. Instead, there are two completely different hubs. One for '47-'59 3/4 and 1-ton with single rear wheels, and one for '47-'59 1-ton with dual rear wheels (these also fit certain '60-'66 trucks). I haven't been able to find any illustrations for these specific hubs. Also, there is only one set of wheel bearings listed for 1-ton trucks (for '46-'52), so both hubs must use the same bearings.
For the 1-ton dually, 18" wheels were used instead of the standard 17", but they shared the same 8 on 6.5" bolt circle.
Of course, all this is moot if ttodd is only interested in the I-beam alone. :p
