Factual error: Dan's wanted poster features a high-resolution 20th Century photo. In the 1870s, particularly way out west in frontier Arizona, the technology to reproduce and print photos like this was non-existent. Wanted posters sometimes had sketches of outlaws, but most often, they contained nothing but the name, reward amount, the crime, and a written description.
Visible crew/equipment: In the final scene, light patterns from studio reflectors are moving on the sleeve of Blue's shirt. He's on horseback in the middle of the desert and is nowhere near water, shiny metal, or anything else that could cause such light reflections.