That was the reason for the title, although I did not get around to discussing Star Trek in this article. Trek is certainly one of the American Scifi shows that owes its existence to the Frontier Mythos.
I'd say yes and no. It was sold as "Wagon Train" to the stars, but not in the generic sense of an old west wagon train set in space but rather as a reference to a popular anthology style TV western of the time "Wagon Train". It implies an ensemble cast of characters and guest characters that show up for one week only. The group moves along and encounters different situations and guest stars in self contained episodes.
So the pitch was not so much about the idea of it being a space western as it was about following the formula of another successful show.