Wrenchman, Your 1st pic appears to show the axle with the "plug" still present in the end of the axle from what I can see (compared to the parts book diagram). Below is a pic from a an
ebay ad offering what is said to be a 1927-28 3/4 & 1 Ton truck axle shaft. It appears in this pic that the plug is absent from the axle being offered for sale. Maybe nothing is actually missing on yours??? Without knowing if the plug is meant to establish axles end play (I have no resources on the axle disassembly/assembly and set up), I can't offer any more help on that topic. Sorry.
Perhaps Dean (Rustoholic) can offer some more insight into the axle setup???
