The split rims on trucks like this do not have bolts holding the ring on. The ring is actually a big round spring, with a split , is pounded and levered off, and pounded back on, when the tire is inflated it should "seat". If everything is clean, and the ring is not sprung. If it does not seat, it can attain low earth orbit regardless what is in the way, people, buildings, etc. hence the reason for a tire cage. A wheel that unbolts in two halves can be a very heavy duty rim, a military rim, or something that uses tires with more than 8 plies, that just will not flex. On that 65' what does it say on the Ford logo plate on the front fender? 16 inch tires tells me 1 ton dually. Never seen a truck with mixed wheel sizes, so I'm 99% sure the axle was changed out. What is under that heavy flatbed that you showed pics of earlier, axle wise? Another thing, I have heard there were a few, darn few, 2 speed axles for one tons, but have never seen one.