As I have been following the AVSIM crash/hack since day 1, I can safely say that whatever they had in their library is gone for good.
It's now up ot the various developers to re-submit them to the new library. This is good for all those products whose authors still follow and care about.
In fact in the immediate aftermath, most of them switched to flightsim.com where most AVSIM stuff can now be found.
However, there will be huge gap in what's called 'abandonware' i.e. products whose authors no longer care about, monitor and busy themselves with. (Typically older and less popular stuff like soundpacks, some panels, repaints etc.) Even in this case though if they're THAT abandoned, then we should have no probs at all hosting locally.