I don't think they could legally sell an out of state resident a handgun
I'm referring to antique handguns, which they can legally sell if they want to (if the pre-1898 ammo involved is obsolete or unconventional, which it is). But this store's policy is that if they have even one round of an obsolete or unconventional cartridge for sale, then it's not obsolete or unconventional. They will sell an antique cartridge revolver to a NH resident, but not a MA resident. But they'll sell me a cap and ball revolver with no background check, no permit check, not even a driver's license check.
Truthfully, with the laws in the mess they're in, I don't blame the store. Antique cartridge ammo is definitely a gray area.