If this were a British item I would say 1964. Leather outfits were very "in" during 1963 and 1964.... and the bold simplicity of the stripes combined with the cool colouring would say 1964 to me.
Even though it's American I'd still lean towards 1964... 1965 at a push (It really does seem to be a result of the Liverpool influence. Very much like the clothing worn by Cavern dewellers in the early 60s, which of course became very heavily copied by the American teens once all the teen mags started heading over to Liverpool to research the Merseybeat Scene and the culture that created the Beatles). I really don't think it would be any later than that.
Vinyl became much more popular for this kind of an item after that, being cheaper (and with it being such a teenage item I doubt they'd go to the expence of leather), easier to care for, much lighter to wear and adpating much better to the silhouettes they were trying to create. Leather was used by the couture designers in the mid to late 60s but their outfits weren't this kind of teen style. Even the chain-mail style outfits made out of linked pieces of leather didn't catch on. They were heavily photographed as people found them so far out, but no-one seemed to wear them besides the go-go dancers that worked at the top clubs.
I wouldn't have thought it was bright enough to be late 60s and the cut of it is all wrong. It has a very simplified shape to it, and a later outfit in the same sort of style would have a much more geometric cut to it and wouldn't have been in leather as leather didn't lend itself very well to the styles that were popular then.
Hope that helps.
love, moons and starrs,
Senti.*
