WOW Your Restoration Looks Great
Normally no lubricant would be used on that bearing [ you could put some Crisco on it if you want but it will wash away pretty fast ] this bearing is normally lubricated with the water detergent and any oils etc that are in the wash water, metal on metal bearings like this were always one of the reasons that it is better to put dishes in the DW as dirty as possible, as this bearing will wear out a lot faster if you rinse everything off the dishes.
The shaft that the wash arm sits on is the wash-arm-support, the motor shaft is down inside the pump and turns at 3450 RPMs on this DW.
Keep us posted on your progress.
John L.