Same BS in the USVI. There were legal to own, but you had to declare firearms the instant they arrived on the island.
But, guess what? Go to the police station and they'd be out of forms that week. Two days later, your house would get raided at 2am and all your guns confiscated. A month later, someone was probably murdered with it. (the chief of police stole a gun from the inventory there, used it to murder his son, and then faked paperwork to say that ownership had been transferred to him. FBI can't touch him, he's been a local senator down there for years)
So, thanks to people that told us, "guns aren't a problem down there, bring all of them you want" we had to keep them hidden and undeclared down there. When my parents finally left, they just gave most of them to a trusted friend that could bribe the proper people to get the paperwork. Otherwise they were going to be thrown in the ocean, which was the option I was angling for.
The family heirloom made it back "legally" but I'd rather not speculate on the form cooking that went into that process.