When Clemmie unfolds the wanted poster, it's creased and wrinkled, but when the camera moves in on the wanted poster there are no creases or wrinkles in it.
Early in the episode, Clemmie says his brother Gavin saw Coleman and figured out who he was. But later, when Gavin sees Lucas, he thinks he's Coleman from a vague description.
Early on, Lucas asks Mark, "How does it feel working somebody else's cattle?" After Mark rides out of the shot, Lucas stays on his horse looking after him with a tree directly behind him and is then seen riding after the cattle. A man with a rifle dismounts from his horse to look at the cattle from behind a tree. The next shot repeats the earlier shot of Lucas on his horse in front of the tree--the exact same footage is used. After the break, the gunman puts down his rifle and rechecks a wanted poster. The next shot of McCain--uses the EXACT SAME footage for the third time (in front of the tree).
The timeline on this show is crazy. In a previous episode, a character was killed and his grave marker said he died in 1871, which was in the present. In this episode, the bounty hunter says the wanted man robbed a train of $20,000 on June 5, 1871... " when I was only 13 years old."
When Ezra and Gavin Martin arrive at the McCain ranch, Gavin kicks Lucas; Lucas flinches BEFORE the kick is thrown.
Clemmie Martin is referred to several times as a kid, but the actor portraying him is clearly too old to be described as a kid. In fact, Harry Dean Stanton was 33 years old at the time he played the part of Clemmie.
During the fist fight between Lucas and Martin. Martin throws a horse collar at Lucas that misses and seems to hit the camera mount. The image can be seen to shake.
While it's not really a goof. It stretches the imagination to think a true farmer/rancher would leave a pitch fork like the one in the final fight scene.