Neal,
The earliest add-on radios from Firestone (made by Stewart Warner), probably from 1932 to 1935 all seem to be designed to attach to the steering column. I've included a few examples. Your controller has "art deco" style numbers so we can guess it is mid-thirties. Have you seen the Philco radio in Paul Gommi's '32 phaeton? Check it out at streetrodderweb.com. The first picture shows a '35 Ford cable controller and a modern radio that hides behind the dash. It is by http://www.turnswitch.com/radio1.htm I bought the octagonal one but since I'll have xm in my '34 pickup I can't use it!