This is really sad but they're going to have to find some very discrete buyers for most of this stuff. They are all so distinctive. I believe the run of the mill dumb thief would have to assume there would be an alarm system in place, which could suggest an inside job or contact. Could be a bunch of average thieves with some good information, now sitting on a pile of extremely hot, identifiable, and unique stolen firearms.
It could also be a "professional" job. They would probably already have buyers, or a buyer, and would have gotten their information in various ways, not difficult since its a public lobby. In this case I imagine it was a walk in the park with no alarm. The news guy mentioned they must have brass balls to steal when everybody could see them, but its not a stretch of the imagination that they might have turned off the lights. Another antique firearms collection was stolen a couple days before this in the same area, which might suggest pre determined buyers.
In the video you can see the locks were ... inadequate to say the least. Thats the sort of lock used to keep ipods behind a case, not the kind you need to secure valuable antique firearms in a public place.
I think the only hope of seeing these guns back is if they were robbed by normal dumbass thieves. They'll have nobody to sell to safely and have a good chance getting caught sitting on the stash the first time the try to sell. Anybody could have walked in there and looked at the locks and lack of security and got away with it. But on the other hand they could be already sitting on the walls of some guys private museum.