Tom Skerritt's character is heard whistling "Frère Jacques" throughout the episode. In one of the final scenes he's shown coming into a ghost town whistling the same tune. But in two close up shots (while whistling), in one his mouth is tightly closed, in another his mouth is open about 3/4 of an inch, from corner to corner. No pursing of the lips that it takes to whistle.
Joe says he thought Tanner was in the Army because of his Jefferson boots, but Tanner's boots are not Jefferson boots. Tanner is wearing calf-high boots. Jefferson boots, properly called booties or brogans, were ankle-high shoes popular in the US Army from the 1840s to the 1880s. They were normally worn by infantry and other foot troops.