Which part are you referring to?
The detailed portion on top of the box is from the Visible V8 engine: "#53 Carburetor, Rear Half."
Then there is the box, a couple of knobs and the metal antenna. I wouldn't be surprised if the real antenna was a part from a Michell record player.
There are several people that makes replicas of these. Elvistrooper (.com) has all the metal parts for instance.