When Argonaut tells Festus to give him his gun, it's said as if Argonaut can see it, but Festus is wearing a long coat and his gun can't be seen.
In the first scene in Matt's office, the boom mic shadow is seen moving on the wall to Matt's right.
After talking to Sam, when Matt leaves to search for the missing townsfolk, he rides off and the scene switches to a rider supposed to be Matt riding away. The rider has a gun on his left side. Matt is right handed.