I finally found the solution as to the Milwaukee die filer with the loose plunger.
Solution was to buy an Oliver Instrument filer out of the want ads! Floorstand model, nuce cast iron stand with filer and motor on a sort of cast tray.
Needs a motor, but the plunger is in good shape and it has the overarm etc.
I cleaned it off, but any more work will have to wait until after NAMM, most likely.