Winegard also used the 6ZD4 oscillator valve in its UHF converters of the time, claiming reduced drift and microphonics, and longer life.
Some of the Winegard models had a Nuvistor IF amplifier. And some had a transistor RF amplifier, either remote-mounted or within the converter itself (although I’d guess not in the UHF tuner “box”.) This used a 2N2966 PNP transistor, as described in a Radio-Electronics 1964 July article.
Thus, a fully-equipped Winegard UHF converter of 1964 had an interesting mix of technologies, transistor, crystal diode, conventional valve and Nuvistor.
Happy New Year!