That's typical of the Sanabria made DeForests sold in company stores in the north suburbs of Chicago. It was made by the American Television School where the students who assembled it paid tuition for the "privilege." Sanabria was at one time also associated with the National Video Corp. which was the CRT manufacturer that later made the infamous 23EGP22 rectangular CRT, which was based on a black and white glass envelope. You might find a little information under the Sanabria name. After writing the foregoing, I found this:
Thank you for the reply. Being a radio guy for all of my collecting career this is all new to me. Thanks for helping a noob out.
SWM
Glad to help. I'm just paying forward, since I learned radio-TV electronics from a lot of nice people who helped me out, back when I was a teen in Deerfield, Illinois.