Your second paragraph has a good point, and I had the same thought upon hearing "It is uncertain whether or not the thief knows what he's got." But I disagree with the first paragraph, which puts the second in a different light.

The stereotypical thief has heard even more often, ad infinitum, about identity theft and the value of personal information. It'd take a particularly clueless thief to not think of checking the hard drive first. A hot laptop might net a couple of hundred bucks, but 2 million Social Security numbers is worth real money to identity thieves.

I'm afraid that cat has been out of the bag for some time now.