BudsGunShop.com - thordson stock

No, your AR must comply with the NYS (Un)SAFE act requirements. If your upper receiver doesn't have any of the "scary" snowflake items: flash suppressor, muzzle brake, bayonet lug, and your lower doesn't have a magazine which holds more than 10 rounds, you can put a Thordsen stock on your AR rifle and make it NY compliant.

It is restricted. I checked their website. Sorry man

Its advertised to turn any AR15 Lower with a carbine buffer tube, into a New York compliant lower. Black Rain has been using them on their New York compliant rifles.
At least that's how I read it.
However I am not a lawyer and am making no determination that I'm willing to be praised or liable for. Good luck!

The AR must be NY compliant to begin with; so the answer is no, "any" AR will not necessarily meet that definition. Otherwise, if the AR is NY compliant then adding an FRS-15 stock (I'm assuming that is what you are referring to) will not make it non-compliant. I'm no lawyer but that is how I read it. SEE the Thordson webpage for legal speak. thordsencustoms.com/media/wysiwyg/IF_YOUR_STATE_IS.pdf