To continue to use the car analogy, a car is considered new until it is titled. So regardless of how many miles it has on it at the dealership, it is still a new car until a consumer purchases it from the dealership and gets the title transferred. Once that happens that car is considered used.
I look at weapons the same way, the gun is new until it has had the initial FFL transfer from the distributor/retailer to the consumer. So I can purchase a gun, take it home, store in my safe, never fire it, and later sell it, the best I can advertise it as is "Like New"
I don't have a good signature.....