Take a deep breath and get ready to be confused.
NY does not recognize "Class II/III" items per se.
NY defines a "firearm" as a pistol, revolver, or short-barreled rifle or short-barreled shotgun. The idea is that concealable weapons are registered.
NY defines a "shotgun" as having a stock for shoulder-mounted firing. I.e.: if it doesn't have a stock, it's not a shotgun.
NY bans any short-barreled (<18") shotguns.
NY bans any shotgun that has been remanufactured (modified) to remove the stock or shorten the barrel below 18".
Thus, if you replace the stock on a shotgun with a pistol grip (only), that's illegal.
If the gun (commonly but not legally known as a shotgun) is originally manufactured without a stock, and has a barrel over 18", it is undefined and thus not regulated. (Strange but true.)
Confused yet?
It gets a bit fuzzy from here.
If the gun was manufactured with only a pistol grip AND less-than 18" barrel, well...I figured that since "pistol" was not well defined, and that Thompson Contenders are registered as pistols, and that the gun in question is a sort of a shotgun-like version of a Contender, and that the legal definition of "firearm" is intended to refer to "short" (concealable) weapons, it's probably be best to formally register the gun as a pistol, which I did so without serious incident (though the clerk did a double-take when I declared the caliber to be "12 guage"). To dot the i's, make sure that your Class III dealer is registered as a "firearm" dealer (a Class III dealer, oddly, can handle Class III "firearms" (aka handugns) _without_ being registered as a "firearms" dealer...and remember what NY defines "firearms" as).
So, to answer your question: it is decidedly NOT a shotgun according to NY state, and is most likely considered a handgun (but the law is a tiny bit fuzzy on that point).
Any more questions? The laws are pretty goofy, and I had to pour over them for a while to figure this out.
[This message has been edited by ctdonath (edited June 19, 2000).]