In 1964, following the release of the Fender Mustang, both the Musicmaster and Duo-Sonic were redesigned using Mustang neck and body blanks. The Mustang body was larger and slightly offset, and was fitted with a plastic pickguard but with the volume and tone controls mounted on a separate metal plate. The headstock was also enlarged. All three models were offered with the option of a 24-inch scale and 22-fret neck or a 22.5-inch scale and 21-fret neck; all three models were also offered with the choice of "round-lam," or veneered, rosewood or maple fingerboard. The 24 inch scale proved to be the most popular of these options. The redesigned Musicmaster was named the Musicmaster II and its stablemate the Duo-Sonic II, both using the Bronco body and pickguard shapes, although decals with and without the II designation were used without any real meaning.

Certain models of the Musicmaster, especially from between 1978 and 1980, were finished with a coat that reacted negatively with the base coat. This causes many modern surviving Musicmasters from this period to suffer from paint flaking off the body.

The Musicmaster was produced until 1982 when both it and the Mustang were dropped in favor of the newer Fender Lead models.

The Fender Swinger, another 22.5 inch scale guitar, was produced using the Musicmaster bridge, electrics and scratchplate but with a modified Fender Bass V body.