...The Supremes can avoid that by basing their ruling entirely on the NYC law being an unconstitutional interference with interstate commerce. It discriminates against gun ranges in New Jersey and Connecticut... I doubt they took this case, which only effects a very small number of people, in order to issue a limited ruling.
The Supremes often take on cases with potential significance only to decide them on trivial grounds. Usually in such instances one of the justices gets cold feet about the big stuff after thinking about it and there isn't a majority on the significant issues without him/her.
So don't hold your breath. It would be wonderful if you turn out to be right, but the odds are against it.