nandohyphen1 you can run
grep "uuid" /boot/grub/grub.cfg && grep "UUID" /etc/fstab
which should output the content of the drive UUIDs; at the top should be one with the flag "set-root" and at the bottom you'll find one ending with a / (indicating the root partition). If both UUIDs match, that's the drive.
nandohyphen1 Also, when you say 'make sure it wasn't installed' do you mean that this could have been installed at the factory or is it something I would have had to install?
This would appear at the time of installation. I'm not sure it does happen nowadays (I haven't installed Windows in a loooong time), but you always had some funky shit happen when dual booting with Windows, where Windows would sometimes overwrite bootloader settings after an update or nuke entries from the EFI system table. And that's also including setting weird places for their own EFI partition (and subsequently bootloader files).
This is why I advise to check first, since restoring grub (if you have never done it before) can be a little frustrating.