Zenith T-line Televisions Models

[drh4683]

Every so often I run across a Zenith TV model with a "T" prefix model number. These were slightly different sets than the regular model year lineup that used the yearly alpha code prefix (Zxxxx for 1969, Axxxx for 1970, etc.). If you look up these "T" line models in the big 3 ring binder Zenith TV catalogs, they were part of what Zenith called the "Royalty Series". They made this series for both B&W and color sets from about the early 60's until the mid to late 70's. After looking through the catalogs for a common theme behind these models, I'm going to assume the "T" was used in the model prefix because it stood for Royal"T"y, just like the "S" models for hotel/motel/institutional use stood for "Special".
The pictures for these T-line models in the big catalog was usually less detailed artwork, like these were the "lesser" Zenith's that didn't even get full marketing attention. From what I can tell these T model sets had slightly different styling from the rest of the standard model year offerings, maybe also with a cheaper tuner like a super video range instead of a super gold video guard. Control panels would be the same physical layout, but maybe they'd change a brushed aluminum control panel insert for one with a metal woodgrain pattern instead, or maybe a slightly different speaker grille. Small changes in the details. Supposedly they were made for retail in department stores? So what exactly was the intent and benefit behind the T-line sets and who sold them?