Perfectly legal if the receiver was made prior to the 94 ban. aside from the Can and what looks like a happy switch. The mags would be legal as well if they are made prior to 94.
Going about a build like that you would first find a M1A with a serial number somewhere below 82XXX, if you want to use a Springfield armory receiver. NYS considers the receiver as the firearm and therefor was legally possessed priorto the 94 ban, just like a lower receiver of a AR15. That rifle is nothing more than taking a barreled receiver from a regular M1A and dropping it into the Sage M14 EBR stock. Acts like a awesome bedding job, increased accuracy but also weight.
This would be no different than everyone else building a tacticool AR15 with lights, rails, FVG, flattop uppers, new cool flash suppressors, new collapasible stocks, from a standard Colt Sporter which had none of those options. Im not saying a FVG or rails ect are evil, just not how it came.
There isn't a law in NYS that states you cannot build a preban rifle to what you want it to be, unless it violates NFA laws.
disclaimer, I am not a lawyer.