Archive-and-install has definitely been around since at least 10.2, if I'm not mistaken. If he reinstalled the OS, that leads me to believe that he did an erase-and-install. If you try to install OS X (say, 10.3) on a hard drive with a higher version (say, 10.3.6), then the upgrade option shouldn't work, and he probably did an erase-and-install (doesn't sound like he did an archive-and-install).
The best option would be to get him to restore his data from his backups.
But if that doesn't work, I'd go with DiskWarrior.