And about the time I "got out" of parts, some oddball thing showed up being sold by Sears or Wards
Frankly, I would bet that your Hanson-Milton are a LOT more common, so what I would do, is just "rig" an adapter. If you can figure out what "they are" buy a matching coupler, and stick one of your nipples into it so that it fits your air hose.