The rectangular strip in the top left corner is what was used in the 19" Zenith Jetliner portables from around 1960.
I have an absolutely beautiful Jetliner in great working condition that needs a tuner. It was used in a stage production in the late 1990s, and part of the play was an argument between two people each cranking the channel knob to their favorite channel. The tuner didn't survive
. At the moment I use it on a tuner subber.