Countertop thinks the smart money is on no. He mentions:
They could either appeal to the Supreme against odds that might eventually make their job much more difficult and result in a decision that would likely undermine much of what they worked for over the last 4 decades OR they could accept the decision and return to DC and pass draconian gun laws, nearly as restrictive but ultimately allowing some right (however negligible) to register new guns while at the same time imposing tremendous regulatory hurdles to any gun shop actually opening up in DC (and therefore undermining that right) and developing a permit approval system that combined with the usual level of D.C. incompetence, effectively accomplishes the same thing as the current ban.Now, if you were Adrian Fenty and Sarah Brady what would you want. The clear loss that amounts to a stake driven through the heart of your barely breathing policy positions? Or a loss that they can easily spin as supportive of hyper aggressive gun laws?
I could see things going that way. But I also wonder what they really have to lose by going to the Supreme Court. I think there’s not much risk that the Supreme Court decision in the Parker case is going to be any more broad than the D.C. Circuit’s. The city can always go back and implement almost-but-not-quite prohibition after the Supreme Court ruling, just as they could now if they choose not to appeal. The ruling will, of course, mean individual right is now law in all the circuits, but incorporation will still not have been established, so I doubt it will have much meaningful effect.
But thats assuming we win, which I think I wouldn’t give higher than 50/50 odds on. We only know we have two solid votes in our favor. We think, but we don’t know, that Alito and Roberts would go along with an individual rights view.  That leaves one more justice to win over, and I wouldn’t want to bet on any of the remaining. If D.C. wins, and I think that’s just as likely as us winning, it’s a huge victory for the Brady’s over the long term. We lose one of our greatest rhetorical assets in this debate. They might want to roll the dice. At this point, they are kind of dead politically, and a rejection of the second amendment by the Supreme Court could resurrect their movement in a serious way.
Strategically though, it would make sense for them to back down for now, do their near-ban, then go back to the courts with a weaker ban, and probably a different, and not quite so clean a case. If I were the city, or the Brady’s, this isn’t the ground I’d want to fight on.
But I think there’s a good chance they might want to roll the dice, and go for broke.