The show has the Cheyenne and Sioux using stirrups. The plains Indians did not use stirrups. They were, therefore, limited to operating as light cavalry.
On set period signage ridiculously advertises "Painting Services"...in a transient tent city that moves along with the rail road and whose temporary citizens could care less about painting anything.
A lot of characters in the series use Remington 1858 New Army revolvers, however almost all of them have brass frames. The 1858 Remington was never made with brass frames, only modern unofficial replicas of the 1858 Remington have brass frames.
Eva's chin tattoo keep changes between black and blue color.