Which was more popular?
How long would it be after introduction to the horse and gun before a tribe encountered Europeans?
To what extent did stories of Europeans precede their advance through North America?
Which was the last North American tribe to encounter Europeans, and what was the meeting like?
These questions will be quite difficult to answer, as I do not believe that m/any NAI groups used writing systems.
However, I can tell you that horses made it to North America before Europeans, as horses came from the south, originating from the Spanish explorers