Again, you are incorrect.Your former home State, New York as well as neighboring States, NJ and RI, all three would jail you if you were found with the hole holster in your possession, with or without a firearm.
The holsters were for single stack pistols and two shot derringers - revolvers need not apply.
Article 265 Penal Law Firearms - Dangerous Weapons | NY Law
Here, find it in the law if you want, it'll be under "disguised guns". 265.02(6) They don't actually ban the holsters specifically, they ban the actual concealed firearm itself, and the paint jobs. Then they had to go back in and revise it AGAIN because TECHNICALLY a camouflage paint job is designed to conceal the firearm...
Because the holster itself isn't illegal until it's used to conceal the firearm and they can't prove "knowingly" or "intent" on an empty holster.
Edit: You can't fire an empty holster...