OEM copies of Windows (pre-Windows 8) generally aren't activated online, they use OEM SLP or SLIC keys paired with an installed certificate and OEM BIOS marker. Unless you install with System Builder or retail media, the restore discs/recovery partition image that come with OEM machines generally come SLIC activated. That being said, the Windows 7 keys on the side of countless OEM machines have never been activated against Microsoft's systems. It could even be the source of this person's keys.
This all changed with Windows 8 though, now OEMs have to embed a unique product key in each machine's UEFI BIOS and activate it online.