I have seen numerous examples of this heater (here is an NOS example).
https://www.flickr.com/photos/advance-design_parts_co/15240469173/in/album-72157631868452754/
It does not meet the mounting example as it clearly has only two attachment studs, and no visible motor.
https://www.flickr.com/photos/advance-design_parts_co/15674350667/in/set-72157631868452754
The heater above and these are the only heaters appearing in the Salesman Data Books and the full-line sales folders (1947-55 1st).
https://www.flickr.com/photos/advance-design_parts_co/8129448404/in/set-72157631868452754
I have no photo reference for this heater nor have I seen one. I will be curious to see if someone has a photo of it and any corresponding hardware.