The 633 was first listed in 1965, and was the first "Dreadnought" size guitar to be offered by Sears. It had a few different pickguards, a few different logos and model numbers, but remained the big daddy JUMBO guitar for its entire run. It was a popular guitar, with a big sound that came from its obviously (and well-touted in the catalogs) larger size, and a ladder bracing scheme for its spruce top.
Fall/Winter 1965 at $54.95
as the 57G633L
Changed to 57H1220L in Fall/Winter 1968
Changed to 57H1221L in Spring/Summer 1970
As the 1221 in 1972 at $66.95