Welcome to ftf. fortunately for me but unfortunately for you I'm not from Jersey.
I recently learned of a case where a man was arrested in your state for an unregistered airsoft gun. It is a safe bet that if you purchase something like that or a bb gun it is not registered. I'm not sure what the process is in Jersey for registering guns but it would not be a bad idea to be double sure that anything you have that remotely resembles a gun is registered. Hopefully someone here can fill you in on the process.