I have a Grendal P-10 (grand daddy to the Kel-Tecs) that I have carried in my back pocket for 20+ years and have never used a holster, 9 years of that riding on patrol with a sheriff's deputy buddy and never had a problem. One advantage a holster would provide is it would keep the exact outline of the gun from imprinting on the otside of my jeans pockets. Most people do not notice an open carried 1911 much less the imprint on a pocket, I doubt anyone is looking a my @ close enough to notice it.
Besides open carry is legal in Missouri so I really do not care one wy or the other.