World body and Western States uses United States Practical Shooting Association (USPSA) rules for scoring and equipment description. Go to their website and check what catagory your gun falls into. Usually it revolves around whether it's a single action (SA) or double action (DA)pistol and what kind of modifications have been made on the gun.
I just shot the WSPFG in Los Angeles. It was the best Action Shooting event Western States or the CA. games have ever had. Great Coordinator. All competitors had to shoot from "duty gear". Not competition rigs with home made jury rigged velcro retention straps.
Good luck in Vancouver and maybe I'll see you in New York in 2011