Buying a handgun in New Mexico (spoilers)

Though Cheyenne is from NY and an American citizen his legal and permanent address appears to be Dublin, yet he walks into a very big, mainstream gun store in New Mexico and immediately buys and takes possession of a very large caliber handgun. This is not legal as far as I know. You have to be a resident of New Mexico or a resident of a contiguous state of New Mexico to take possession immediately. You do not need a permit or background check if you are a resident. If you are from a non contiguous state you can buy it but it has to be shipped to your home state where it would be subject to the permitting laws of your home state, meaning, you will likely need a permit.

I guess they did this for the convenience of the story, or they are implying gun dealers in New Mexico routinely break the law in order to get a quick sale. New Mexico is very loose in their hand gun laws for residents, you don't need a permit if you are over 21. Apparently, Utah is the same, very lax.