The Gibson ES-120T was an entry level thinline electric acoustic available from late 1961 until 1970. Built at Gibson's Kalamazoo plant, it was first included in the September 1961 price list, at $149.50 (US zone 1); though shipping statistics show only one instrument left the factory that year. It was the cheapest electric acoustic guitar available from Gibson, and was comparable in price to the solid body Melody Maker D, at $147.50. In total 8895 ES-120Ts were produced, with 1965 the peak year.
The ES-120T and it's very similar Epiphone equivalent the Epiphone Granada that first shipped in 1962, were really nicely made guitars. They were entry level instruments, yet certainly not built to lesser standards. Gibson may well have added fancy inlays and to it's more expensive guitars, but the humble ES-120T still got the fine body and neck woods, superbly assembled and finished in nitrocellulose. It's true, as players, they don't have the same range as the other ES guitars, lacking cutaways, and the PU-380 'Melody Maker' pickups were certainly less powerful than Gibson PAF humbuckers - but in terms of build, these guitars absolutely exude 60s Gibson quality.
The following description is taken from the 1970 Gibson Thinline catalogue
ES-120 T Good looks, fine performance and low price. These are the qualities that have made this electric Spanish guitar a favourite with amateur musicians. Features an exclusive, patented finger rest pickup.
FEATURES: Arched maple top and back, mahogany rims. Slim, fast, low action neck joins body at the 14th fret. Mahogany neck, adjustable truss rod. . Rosewood fingerboard, pearloid dot inlays. Adjustable rosewood bridge, chrome-plated trapeze tailpiece. Powerful pickup mounted off the body in finger rest. Individual tone and volume controls. Cord jack mounted on finger rest. 16 ¼" wide, 20 ¼" long, 1 ¾" thin; 24 ¾" scale, 20 frets.
ES-120T - Sunburst finish
519 - Faultless plush-lined case
304 - Archcraft plush-lined case
104 - Durabilt case
ZC-19 - Zipper cover for 519 case
See also the shipping stats for the Epiphone Granada here
Despite first shipping in 1961, the ES-120T was not ready early enough to be included in the 1962 Gibson guitars and amplifiers catalogue.
From the 1964 Gibson electric guitar and bass catalogue
Created for a volume market, a new electric Spanish guitar with an exclusive patented fingerrest pickup. Superb Gibson features and tonal versatility, available at a popular price
From the 1966 Gibson full line catalogue
Created for the amateur player
The 1970 Gibson thinline catalogue
Good looks, fine performance and low price. These are the qualities that have made this Electric Spanish guitar a favourite with amateur musicians