Yeah, the Musicmaster and Duo-Sonic (the early non-offset versions) came out in 1956 so it would have been their first year. Prior to that a Tele really would have been the base level, well that or an Esquire.
I'm kind of an obsessee of cheap student models, including Fenders (I made a whole website on the old Harmony guitars you could get in the J.C. Penney catalog for example), it's kind of a "Sickness" I have. Some of the weirdness in those guitars gives them a certain "Charm".
The Mustang was added in 64', was the first one with a Vibrato and an offset body, and the longer 24" Scale of the Fender Jaguar (before that the student models were 22.5" Scale, which was offered as an option on all three until the late sixties due to lack of sales of the 22.5" neck models) - the Musicmaster and Duo-Sonic were redesigned to use Mustang offset bodies in 65', and in 67' CBS introduced the Fender Bronco (different vibrato from the Mustang and a single bridge pickup).
The Musicmaster, Bronco, and Mustang lasted till 1981
The Mustang was so popular in Japan due to Char that Fender did a special run called "Mustang 84'" in 1984 that was sent to Japan, non-serialized vintage-white Mustangs made in the Fullerton plant with maple boards and black pickup covers, or rosewood boards and white pickup covers.
The Duo-Sonic lasted till 1970.
There was also a short-run model with 3 different names (Musiclander/Swinger/Arrow) that was basically a shopped down 5-string Bass body (Bass V) shaped like a metal-version of a Mustang body setup as a 22.5" Music Master to use up parts. That ran from about 1969-1971.
