Matt refers to his friend as the best lawman in the state of Arizona. Arizona wasn't recognized as a state until 1912, which is a bit late for Gunsmoke, although not at all impossible. Although grave markers in the first season date the beginning to 1883, thirty years before that, the show never observed strict chronology in anything.
When Masters is up on a roof, waiting for the Apache brothers, Matt is in the middle of the street and tells him to come down, or he's coming up after him. The camera changes to Masters, who shoots at Matt. The camera changes back to Matt, but it is obviously his stunt double, looking down and to the left, instead of up at Masters. As Masters' bullet hits the ground in front of him, Matt/double takes off to the left and jumps over some sacks, into an alley.
After Festus leaves the diner where he had been eating with Doc, there is some muffled background conversation of men and women talking. However, all of the customers in the diner were male.