I'm new to IDPA shooting and wanted to ask a question please. I realize there are things you can and can't do to your gun to help you achieve better results. I was reading something today and was wondereing if I could have this item installed onto my Glock 19 to help me shoot better? COMPETITION 2 M THUMB REST ? It looks to be a great idea to help keep your thumb secure and in place but is it legal to have? Thanks for your help.