You are correct in your first sentence.
As to the second, it’s a much-better-than-usual shot that SCOTUS will grant cert, because the DC decision created a “circuit split.” SCOTUS correctly abhors a circuit split because it means, as a practical matter, that federal law means one thing in ONE part of the country and a different thing in another.
I predict that either the SCOTUS will not take the case or it will take the case, but overturn on the standing issue rather than addressing the arguments on the merits. First, there really isn't a direct conflict between Circuits because Parker involves Federal regulation, whereas the other cases (except for Miller, if I recall correctly) involve State and local regulation. Until such time as the SCOTUS decides whether the 2nd Amendment even applies to the states through the 14th Amendment, Parker is of little relevance to the "conflicting" cases in the other circuits.
Second, if I recall correctly, the threshold issues in Parker concern the plaintiff's standing to sue and whether the case presents a justicable controversy. The SCOTUS can easily sidestep the 2nd Amendment issues by reversing the Circuit Court and ruling against the plaintiff on these threshold issues, which would result in the dismissal of the lawsuit and prohibit other courts and litigants from citing Roger as binding precedent.