Some of the early S1 episodes have a Westernish, "settling the frontier" feel to them, though.
Rare 1966 Video Interviews with William Shatner and Leonard Nimoy On The Set
interviews were taped just prior to Star Trek's NBC premiere in September 1966 on the set of the episode TOS "What Are Little Girls Made Of?"
these clips are historic moments with the 2 main stars of The Original Series discussing a show that has yet to be seen by the public.
Shatner likens Trek not to a Western but to how Naval forces patrolled in 18th century.