I have been through livestock checks. You do have to prove the animals you are carrying have their shots and required tests. But as far as weapons the officer in the car can call in the serial numbers to see if the weapon is stolen. Beyond that I have never been asked to prove anything more in over 35 years of travel.
If you are returning from a hunt there are regulations regarding how you handle the meat due to outbreaks of chronic wasting disease. In NC when returning from a hunt you can't bring any part of a game animals spine or brain back into the state. I don't know if people passing through have to meet the same requirements. To be on the safe side it's best to leave the brain and spine of what you kill in the state you killed it. I would hate to know I wiped out the local deer or elk herd because I didn't cut up meat properly.
"I do not aim with my hand; I aim with my eye. He who aims with his hand has forgotten the face of his father.
I do not shoot with my hand; I shoot with my mind. He who shoots with his hand has forgotten the face of his father.
I do not kill with my gun; I kill with my heart. He who kills with his gun has forgotten the face of his father."
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