Why pay that much for them when you can get them cheaper? I wouldn't waste time with Ford parts when you can get the correct GM stuff instead.
Another thing I believe won't allow the fitment of the Ford rotors on GM's: hat depth of the rotors. Even though the bearing hubs may be the same or fit the same, the hat depth of each can be different in where it won't allow the proper fitment of the calipers since it would either put the rotor too far out or too close in to the caliper mounts.
If you are really bored, go to your local parts store and have them pull bare rotors out and measure them to check the differences.