No,I don't shoot a '92. In matches,I actually use a gun that you're going to dislike even more-a Marlin Cowboy. My pistols are 1875 Remington reproductions in a historically correct gun rig. I do own a '92 and a Ruger Vaquero,I just don't shoot them in matches.
SASS does recognize those who shoot BP and use historically correct firearms. SASS has a BP Cartridge class,and a Frontiersman Duelist class for those using C&B pistols. So,if recognition is all you're after,then SASS already has you covered. And,correct me if I'm wrong,but NCOWS doesn't require the use of BP,does it??