After Bat tells Billy that he's going to the casino, the view changes to the same street scene that has been used for different towns in several other episodes.
The announcer states that the episode takes place in 1875. The gunslinger tells Masterson that they had met in Tombstone earlier. Tombstone, Az was not founded until 1879.
At the beginning of the show; the announcer says that Rapid City, SD was the terminus of the transcontinental railroad in 1875. The transcontinental railroad ran cross-country over 200 miles further south.