Not an expert; what I think jdpigeon is referring to, though, is that the information storage is just fine, even if the indexing mechanisms aren't.

Like recovering data from a broken filesystem - the directory structure is lost and for a normal usecase the data might as well be gone, but a lot of the content is theoretically there and recoverable if some indexing system (even one different from the original) can be created.

Yes! It hasn't been demonstrated in mammals, but in the elife paper linked above, I think they saw synapses regrowing in the same positions. However, its not clear if it's actually necessary for them to be in the same position.