Foundie a roundie!

[Jeffhs]

That cover below the VHF channel selector might be a UHF knockout plug. Many TVs in the early sixties (before April 30, 1964, the date all TVs sold in the US had to have all-channel tuning) had these so that an optional UHF tuner could be installed; the upgrade kit included the tuner, knobs and all hardware required to mount the component in the set. The plug covered a hole in the tuner cluster through which the UHF tuner shaft protruded. I've seen several sets like this in my 30-odd years of electronics experimenting. One such set that stands out in my memory, even after all these years, is a 23" Sylvania console of early-'60s vintage owned by my aunt and uncle; the set was VHF only, and had a knockout plug marked "UHF convertible" below the VHF tuner. The set went West some time in the seventies and was replaced by a 15" Admiral all-channel color portable.