Eric,

That tuner sounds identical to one in a Raytheon chassis I had many years ago. The knob looks identical as well.

The Raytheon was from the early 50's and had a 17" rectangular all glass tube, which was mounted on the chassis. Both the tuner and the set worked very well.

I'm wondering if Raytheon could have built the set you have for Sonora? I seem to remember dimly that Sonora might have been a store brand, like Silvertone, but I'm not certain about that. If you can't find any information on it in Sams, try looking at Raytheon models of that era to see if you can come up with a match.

Bill