Other mistake: When Rango is loading his revolver during the stand-off, he loads the bullets on the right of the revolver, however, the chamber is hanging from the left of the revolver.
Other mistake: When Rango and Rattlesnake begin walking toward each other and the clock strikes noon, there are only eleven chimes, not twelve.
Answer: I think he was a ghost... in a way. He was like Rangos guardian.