Well, first off, with a home made firearm you can put whatever you want on it for a serial number, soc. sec. #, birthday, aniversary, ABC123, etc., etc. If you keep it for yourself you dont even have to mark it although ATF does recomend you do so in case of theft.
Secondly, you may sell or give away a firearm that you have made but there is an unspoken number per year that if you go over you are considered as "manufacturing" and selling as a business and must have the proper FFL, etc. 1 firearm now and then does not count.
Thirdly, New York's ban is an exact mirror of the defunct federal AW ban, you can build any rifle as long as it is compliant and if it is a bona-fide "pre-ban" receiver (pre 94) you can have all the evil features you like, just as it used to be in the rest of the country but unfortunately wont go away here.
I am not offering this up under any illegal transaction, if anyone has ideas of getting this in an innapropriate manner they can forget it, as the unit stands right now it may not even qualify as a "firearm" as it is basically "deactivated" and cannot be made to function without being repaired so all other legal questions may be a mute point. I however will endeavor to keep any transaction completely legal.