The one with knobs does say STEREOPHONIC on the front so radioactive is quite right.
They could also be thermoplastic from the late 1950s.Those Bakelite knobs...gotta be late 40s or early 50s? But stereo wasn't until the late 50s. So the knobs are kind of a throwback IMO. Yet another aspect of the unique styling.
A word so nice, they wrote it twice!Actually figured out the writing.its supposed to say stereophonic just like on the other side.
That's what I thought.They could also be thermoplastic from the late 1950s.
Keep us informed.Thanks guys! Didnt see the stereophonic this morning without my glasses. Think I'm going to scoop these things up just for the cool factor. Hopefully it works out.