My Kimber Tactical Custom II has serrations UNDER the trigger guard. This seems to help bring the pistol back on target quicker.
I just pulled my Glock 19 out of the nightstand and reached my weakhand index finger out to the front-serrated trigger guard. (After removing the Streamlight M-3
) It just didn't feel natural. I think recoil might even pull the weapon away from the weakhand index finger making you have to reposition your hands to reaquire your grip.