Seems like much of the counter culture movement derived from bad portrayal of earlier TV. Long hair, beads, style of clothing.
More to the point; long hair banded Indians riding wild. Anyway, not a very coherent question but one I've always been curious about.
Many of the older Indian Tv shows pre-dated the long hair of the sixties and was wondering if this style was borrowed from
Ah, the Rock and Roll Age (1953-1963) affecting the Rock Age (1964-1973)...
There was a definite fashion in the Rock Age referred to as Indian Culture. It was a conscious adoption of beadwork, fringe, moccasins, headbands, and braids or other long styles. It was connected both to exploring native spirituality and being anti-racist (like white guys in dashiki shirts). But I don't think it was via the six dozen Warner Brothers Westerns series.
You need to remember there were two shaggy predecessors to hippies: beatniks and surfers. People complained about them being long-haired, though it was rarely past the shoulders.
Still, it's an interesting idea. It might not have been an immediate cause, but things wander around in the back of the mind.