[drh4683]

You are correct that its a 1975 chassis model, but the first figure in the model number identifiys the model year for the TV. "G" being a 1976 model. In cases like the 14N22, it is indeed a 1966 chassis model, but zenith continued to produce it in their cheaper B+W consoles up until around 1972. Your zenith console that uses the 14N22 probably has an "A" as the first figure of the model number if its a 1970 model, or "B" if its a '71. Zenith did the same thing with radios. I've seen some "N" series chassis being used up until Zenith's very last tube radio (the Z316 for 1969). Basically, the chassis never changed from the original design and they just kept producing it but putting it in different cabinets and as sets are sold each year, they update the model number so its model year can be identified.