Yeah, NYS sucks. CA sucks (I apologize for Feinstein, although I never voted for her), but not as bad as NYS, for now. 7 rounds is ridiculous, and was strategically selected. It will make over 90% of all semi-auto pistols illegal, until the manufacturers produce 7 round mags. The round count in your mag won't matter, as the "law" requires a magazine capable of holding no more than 7. Same thing in CA with the 10 round limit. Fortunately in CA, higher capacity mags were grandfathered, and I have no shortage of them.
If a person is subject to the law, and wants to be "legal", even with your original mags, design a magazine plug, like used in shotguns. Or wait, and someone will be selling them soon. Or wait, until the SCOTUS tells that governor what he can do with his law.
In regards to off-duty and retired LEO's, the LEOSA/HR218 trumps NYS law. The law specifically addresses interstate reciprocity, but also applies to the officer within his/her own state. The only restriction on the weapon and ammo is it must be "of similar type as that approved for on/off duty, by the issuing agency" (it's really no more specific than that). So if NYS on-duty cops can have more than 7 rd. mags, so can off duty and honorably retired NYS LEOs. If, by some chance, they don't exempt the on-duty cops, and they become restricted, the only people allowed in the state with 8+ mags will be the military, federal officers, and any retired or on/off-duty officer from any other state. The whole thing is stupid. Just stupid.
Life is tough. It's tougher if you're stupid. -- The Duke