There was even a recent high-profile Supreme Court case that eliminated the historically-common (the majority opinion was simply wrong about the history, just, straight-up factually not correct) practice of sharply limiting carry of firearms in towns and cities, let alone ownership. So no, guns aren't meaningfully illegal in NYC, besides the fact that they're extremely not-illegal outside the city and it's not like they frisk anyone on the way in. Like, right now, guns are kinda the least illegal in the city that they've been in more than a century.