In NY, the law reads the resident in question must have owned them in 1994. Technically, under the law, you cannot possess any pre-ban high-cap mag if you did not own it in 1994. In fact, the law has NOTHING on transferring them to others even in the event of death (apparently you're supposed to trash them).
Now, nobody (and by nobody I mean nobody outside of Long Island, the major upstate cities or possibly Ithaca) actually enforces that little bit, and most gun shops have pre-ban mags everywhere for sale, but technically you're not allowed to have them.
That gray area is what is preventing me from putting a folding stock on a 1973-era 10/22. Legal? Technically no. Enforced? Not really. I just don't want to take my chances, even with the very red DA and judges in this county. A piece of tubing and a hinge aren't worth 7 years in Attica.