Got the new factory style grips for my GP100 today [ rubber with the wooden inserts] to replace the large black grip it came with--No problem installing the grip, but what is the purpose of the short length of brass or copper rod that's lying in a groove inside the one grip panel? Take out grip screw, remove grip panels, remove the large short pin, install grip, push large pin through until centered, replace panels and install screw--what is the little section of rod for?-----do any of you know why it's there?----