azguy,
It's a Model RA-106 Manchu, one of the expensive DuMont sets. Uses the 20BP4 CRT, multiple chassis'. It was designed to be placed right up against a wall, the main "box" swivels on a eccentric "lazy susan" that allows the screen to be moved into viewing position. When not being viewed you would turn the set back so either the mahogany or green side was shown depending on the room decoration.
Here's a link to my set:
http://www.myvintagetv.com/dumont_manchu.htm
You should probably make sure the CRT is good, as it is as rare as a 15GP22. There was a modification to allow a 19AP4 to be installed. If you do buy it, and before you move it, you may want to remove the focus coil assembly from around the neck of the tube, the main CRT support is the wood bracket which compresses the face into a large rubber mask. This is from experience, I broke the neck of the crt when the cabinet got away from me taking it off the truck with a refrigerator dolly.
If the CRT is good, $300 is a great price. This would be only the 7th one I've heard of, hope there is something still inside. One I found a couple years ago was completely gutted.
Chuck