By the looks of that set it is certainly apt to be pre-1964--the year UHF was mandated on all models. The VHF tuner may have had a position for UHF (IIRC Zenith was cutesy with this and it looked on the knob like a siamesed-together U-F.) but the UHF tuner may not have been included. A '59 model I had was like this. I did try to incorporate a built-in tuner but ended up instead opting for a UHF converter that operated through CH 3.
http://images.google.com/images?hl=e...-8&sa=N&tab=wi shows an assortment of space command controls of the time.