Benjamin Wolf (The Elliot Schlissel New York Law Blog) has a guest-post from the petitioner in Maloney v. Cuomo that reports this.
Kirkland & Ellis (which is doing this case pro bono) is a top-notch law firm, with a top-notch Supreme Court practice. My guess is that the Supreme Court would prefer to consider the incorporation question in a case that involves more common facts, and that doesn't raise the additional legal question of whether nunchakus qualify as "arms" for Second Amendment purposes. But it's hard to tell for sure: It's possible for the Justices to use the case to decide the purely legal question of whether the Fourteenth Amendment incorporates the Second Amendment and thus constrains the states to respect an individual right to keep and bear arms. The Justices must be aware that the question is out there in lots of cases.
Moreover, the main criterion for choosing whether to decide a case -- whether there's a split among federal circuit courts or state supreme courts on the subject -- may well not arise on this issue: The existence of late 1800s Supreme Court precedent against applying the Second Amendment to the states (in a case that also held the same as to the First Amendment, a view that the Court has long since rejected) may keep a split from developing in the first place, as lower courts conclude that they're bound by the precedent despite the Court's relatively broad embrace of incorporation throughout the 1900s. So it's possible that the Court might conclude that there's no time like the present to decide the issue, though I'd still guess the odds are against it, even with Kirkland involved.