No, no...the Unreal Engine 3 is universal. It's designed for anything.
I'm just saying that Gears of War was designed from ground up using the Xbox 360 hardware, so bringing it to the PC will most likely be a port due to the variation of hardware that the PC has. Gears of War was developed from the beginning with the Xbox 360 in mind, not the PC. It is possible to bring it over to the PC, but it just takes time. It might happen, it might not.