Can I scan the hard drive for something common among all wallets to identify? Thanks.
Yes, which is why it's pretty useless to rename the file. If you want to protect the contents, use a secure password. If you want to hide the fact that you even use bitcoin, then get the file off your hard drive and hide it physically somewhere, but modifying the name is nothing more than a false sense of security.
It's been a while since I poked around in wallet.dat, but if I recall correctly I think you can search for the following sequence of byte values:
0x63 0x6B 0x65 0x79 0x21 0x03
While there may be better things to search for (and someone more familiar with the file than me will probably stop in here to help you eventually), there's a pretty good chance if you find that sequence that you've found a Bitcoin Core wallet.dat