A couple goof-ups.
The story is set in 1863. Yet, one of the characters conspiring in an ambush mentions Custer's Last Stand (which was then-thirteen years in the future)!
Then, there's Glenn Ford's sidekick. An alleged explosives expert nicknamed "Nitro." He's depicted as riding--at full gallop--with bottles of nitroglycerine in his saddle bags! An action that, in real life, would have caused that notoriously unstable chemical explosive to detonate at the first intolerable vibration.