I don't think you understand what is on that page. lol
One wise would understand that since iOS 7 is the biggest change we've ever seen in iOS, chances are higher to see a different release build.
But doesn't the GM have to be loaded onto the new iPhones NOW to be ready for shipment and sales? What is the likelihood that Apple would preload a GM onto their new devices and then push out a different build a few days before those devices go on sale?