Yeah, there is a little resemblance. Both songs are in the key of Dminor, and both share melodic phrasing...without any duplication, though. "Ghost Riders (in the Sky)" was definitely an inspiration for Morricone's "Titoli" from "Fistful of Dollars".
Most of you may already be aware of this, so forgive me if I am repeating old news. But, Morricone was heavily influenced by some late 50's and early 60's instrumental groups (and individuals) such as The Ventures, Duane Eddy, and so forth. He was influenced by such performers so much so that he was a member of an instrumental combo called The Electronic Men (can't recall the precise Italian name of this group, at the moment..but, that is what the name translates to). This group also featured Luis Bacalov, Alessandro Alessandroni, and others who later found work scoring Spaghetti Westerns.
In addition to The Ramrods version of "Ghost Riders...", you should check out the Lively Ones' version of the "Theme from Exodus"! That really sounds like a theme from a Spaghetti Western!