Musette, circa 1971
This is one of several vintage styles that bear the Musette name. This version features a collar button closure, which was soon replaced by a turnlock in 1972. The strap on this variation was also sewn directly onto the back of the bag.
Photos courtesy of @ranunculus.nerone.vintage
Ad from 1971
Original Cashin for Sills ready-to-wear photos featuring the Musette as an accessory. Courtesy of the UCLA Library.
This is a really nice comparison of both Musette models side-by-side. Note that not only is the closure type different, but so are the strap attachment points.
All photos courtesy of @ranunculus.nerone.vintage