It's not just the guns...,
As I wrote before, I give TV and movies a break in the 1960's and 1970's...., and prior. But imagine had they done
Last of the Mohicans c. 1992, and put
Magwa in a full Sioux War Bonnet?
Then you get John Milius directing
The Wind and The Lion, and the Marines storm the port of Fez in proper uniforms, with .30-40 Krag rifles, and later some are seen with pump Winchester shotguns, which were what they would've carried, and that movie was done in 1975.
I don't mind that Spencer Tracey in NW passage is running around in a glengarry hat, with "muskets" that are actually trap-door, Springfield rifles.
Or that Fess Parker as Daniel Boone often looks like his shooting bag is empty and it's too low and so is his horn,
, or that the Brits in
Allegheny Uprising have the wrong guns, etc etc
LD