I can't find any really concrete info on this, but I have lots of wobbly info which leads me to believe that allowing a handgun to exist in NYC in any form is a bad idea.
Caution--New York is the only state that prohibits the transportation of handguns without a license. Travelers should therefore be particularly careful since they face severe consequences should they inadvertently violate the state`s highly restrictive statutes.
There was a thread over in the Washington forum which somebody had briefly touched on the topic:
Shad0wfax's story of how a diverted flight to NYC could land the traveler in trouble with the law if he had checked a firearm mirrored what I had previously heard (although I don't know where from).