Odds are, Matt, that the old files may only be but 'ghosts'. Also, if they are there, then the files were protected and have only been hidden. However, my money personally (and I'm really kinda dissappointed too) is betting on that the old files from the pre-hack period are either gone gone, or the that if they are there, the files are, how to put this? Empty? Empty as in, just the file name and extension exist, and nothing else. And that the permissions only have the name, and not a copy of the actual documents or files.
But, I'm pretty well aware that regardless of the safety protections, odds are at least 1,000 people can hack through. But, might as well as keep as many people from hacking. The more determined the are, the more likely they will hack through. However, odds are, this will be a very rare occasion indeed given there is little of interest to an intelligence person or to any corporate or government angency, regardless of the postings. Even the profiles don't require too much as I recall, at least not important information like SSN for us Americans or the equivelent elsewhere. Government facilities are more likely to get hacked. Truthfully, it could have been simply a fluke, though I highly doubt it. Only time can truly tell for sure.
On the side, a blank slate isn't always good, nor is it always bad. It just is. All things no matter how big or small must come to an end.