Computer_Commando,
Thank you for sharing.
I doubt that was an accident.
More likely Microsoft did it that way on purpose. It could have made upgrades easier for the OEM, Dell, to do upgrades. But Microsoft would have little, if any, resewn to tell the world how easy it would be to upgrade a Dell Desktop to Windows 10.
You might guess that the BIOS had a secret area that shows what OS was shipped out for Dell when is was first shipped out from the factory. That would not be hard to implement, and save Microsoft server time spent of having a server validate the system in a database. Just fetch a secret code from the firmware.