Character mistake: Reward poster on the pillar for Matt says "Matt Dillion", not Dillon.
Factual error: In the opening dialogue by Matt Dillon on Boot Hill, the last shot of a tombstone has the date of 1982.
Suggested correction: It's not a "9" but an "8." The two 8's don't really match, but you can see the other tombstone with a similar "8." It's 1882.