From the looks of the nozzle, belt lifter, and foot switch, you have something around a model 516 or later - like late 50s to early 60s. The model # should be under the motor unit.
Pretty sad it was shipped with a full bag - you were brave working on it inside! I would have dumped the bag in the snow...
The screw hole in the emtor is for the Sweet Aire dispenser - it was for making the bag smell better. Cork it with a screw for now.
Despite its current condition, I bet it will fix up nicely.
Pull the motor case off, turn it on and look for excess sparking at motor brushes. If good, then tear it all down to the last screw, wash/clean every part, polish the metal with Mother's mag & aluminum polish and a wheel in your drill, replace bearings, replace motor brushes if less than 1/2 long, replace/repair anything else that is broke. Reassemble carefully and enjoy it for another several decades!