The Night of the Big Blackmail - S4-E1
Continuity mistake: Before and after the first freeze frame, West's hair is combed from the right side to left. During the next scene when West's hat comes off during the fight, his hair is combed from the left side. In the next scene in the boxcar, his hair is back to being combed from the right. In the last scene of this episode when West is in the boxcar, he has a completely different hair cut. It is much shorter than in the previous scene, very flat looking, and is parted on the left. This last shot makes Mr. West appear to have a receding hairline.