First of all, when a plane is sitting on the landing gear/wheels, the CG doesnt really have anything to do with where the center of rotation is, does it? It sitting on the gear... what has CG have to do with it?

Secondly, do the geometry... the gyro senses a change in angular movement, which is identical anywhere on the airframe, as was stated. Think of it this way... pick up the plane, and change the "heading" 90 degrees. Now place the gyro ANYWHERE on the airframe, and the gyro also sees a change of heading of 90 degrees. How much translational movement it experiences while rotating is not relevant... only how many degrees per second it is moving - which remains constant regardless where it is located.

AJC