Wyatt Earp is portrayed as being Tombstone's local Marshal in the week leading up to the gun battle of October 26, 1881. In fact, his older brother Virgil was the Marshal, with younger brother Morgan as deputy. Wyatt, a saloon keeper, was deputized as an emergency measure while the brothers were walking to the site of the battle.
Johnny Ringo was not in Tombstone during the October 1881 gunfight at O.K Corral. He had an altercation with the Earp faction the following year.
In reality, Pa Clinton died 11 weeks before the gunfight at the OK Corral.
When telling Earp that Steven has gone with Johnny Ringo, the Doctor refers to him as "she".
Doc Holliday's common law wife Kate speaks with an exaggerated American accent, but probably really spoke with a Hungarian accent.