'Glory Guys' inspired TV show?
The timing seems too tight since Glory Guys (http://www.imdb.com/title/tt0059232) premiered in July '65 and F Troop debuted in September '65, but the movie featured a whole incompetent troop out in the west fighting Indians and I remember thinking as a little kid watching back then that it had the same vibe of lovable but challenged soldiers... (except in the movie the danger is real)
The TV show does resonate of a producer watching a movie western and thinking: "We could make a comedy out of f-ups fighting Injuns!" and Glory Guys does seem like the perfect inspiration...