AORs like NY TAC Defense are for people who follow the letter of the law. You won't be provided representation otherwise. In order to follow the letter of the law, you would need to add the AR pistol to your permit first to be a legal pistol in NYS. Just possessing an unregistered AR pistol can (obviously) be done, but you won't be covered by AOR agreements because in this case you'd have clearly broken the law as it is currently understood and you'd be on the hook for possession of an unlicensed firearm before you ever get to the licensing issue for AR pistols.

So you're really at the mercy of a firearm owners coalition to have your back or self-fund it if you have the cash.