I think the differences have all been mentioned.
The barrel will be longer. The receiver won't have the gizmo that catches and then releases the hammer in burst mode (so it doesn't just follow the bolt as it goes forward). It won't have the cams and whatever to fire three shots and stop. It won't have the third position for the selector switch to activate all the gizmos, cams and whatever to fire three round bursts.
The parts it does have will more than likely be made out of the same stuff to the same degree of accuracy as the military version.
One thing you might check is the rifling. The military rifles are one turn in 7 inches. Many manufacturers use one turn in 9. The combination of the longer barrel and 1:9 rifling means a higher muzzle velocity for any given ammunition. So don't count on using the military 25 m zeroing approach.