Norm's right, Phillip, we figured about 1924-26. Found some patent dates on the data plate, and the last one is 1924. Also I have a copy of a Royal newspaper ad from 1926 showing the more modern machine with the bag connection on the same side as the later models, so this one is somewhere in between.
And Norm, I've already started working on it! Got the bag off and vacuumed it inside and out. Also replaced the motor brushes (one was completely gone, the other was almost gone) and hooked a test cord directly to the motor. The good news is that it runs and sounds pretty good. The bad news is I think the armature is shot, as it sparks enough to light up a dark room. However, I'll still procede with the cosmetic restoration, then when I find an armature, or someone to rebuild the armature, everything else will already be done.
Jeff