On October 12, Microsoft provided system builders with the Windows 7 OEM Preinstallation Kit (OPK) tools and related documentation they need to preload and customize Windows 7 on multiple new PCs.
System builders are custom PC integrators. They are a lot smaller than the 20 or so PC OEMs who received the final Windows 7 bits and tools just days after Microsoft released Windows 7 to manufacturing in late July.