I say if you can cancel the order, do it.
Microsoft, in their neverending quest to keep things as complicated as possible for the end user, no longer has COA stickers on Windows-tax'd computers. The Windows 8 license key is now embedded in the mainboard's ACPI, the MSDM table.
Install Windows 7 without activating it. Download and run one of two applications you can use to read the MSDM table: RW-Everything
or if that doesn't work (it would hang, become unresponsive, and start eating up RAM on my Thinkpad X1 Carbon running 8.1) the Windows 8 Product Key Viewer from the MyDigitalLife forums - I honestly consider the latter a worthwhile resource, but they remain "potentially seedy" so download and run at your own risk.
Once you have your product key, go ahead and create an 8/8.1 install USB stick or DVD and get yourself back up and running. I've read that technically the vanilla, straight from Microsoft, Windows 8/8.1 installers should pull the key right from the firmware automatically regardless of OEM - which is behavior new with Windows 8, as with Windows 7 that would only happen with OEM-provided media. In practice, this was not the case for me.