Emailed DNROI, and only got a reply with a link to the rules. I included pictures and was very polite and professional, and only ended up with information I already had and no clarification. The rules of appendix D7 21.4 state, "Grip modifications such as, but not limited to, undercutting/smoothing trigger guard, adding or removing finger grooves,...., without reference to Appendix E4." So does this mean it's pretty much a free for all when it comes to CO grips?