Given the volume of the data and previous experience, the disks would restore the computer into the same state as when the were created, including all the user files at the time.
Oh, it's that kind of backup? Then yes, your best bet is trying to fake out or patch out the checks. I assume you want to keep the real files private and not just upload them to the Internet. Does the computer you bought have the same backup software on it? If so, can you make a dummy backup with it and then upload that somewhere instead? Then someone could figure out how to crack that one, and you could then follow the same steps for the real one.