I can't answer your question, but find myself in a similar situation, buying a "reconditioned" laptop that didn't come with restore media at all. I'll be monitoring this thread, and hopefully someone will have a simple answer, since your question seems straightforward enough.
While it's a bit more work, running an MD5 checksum against a known genuine DVD would at least let you know if the files have been tampered with.
This reminds me of an occasion when I accidentally bought a counterfeit DVD from an Amazon Marketplace seller, actually of Amazon's own Createspace DVD-R...a bit like counterfeiting Monopoly money IMHO. After weeks of going back and forth with Amazon customer service, asking them to simply verify the front and back case artwork, I gave up and just returned it to the seller.