Found this to be a good read.. From 2017
http://web.archive.org/web/20220324192218/https://www.historynet.com/packing-iron-real-old-west-differed-way-done-movies/Packing Iron in the Real Old West Differed From the Way It Was Done in the Moviesby Lee A. Silva 8/17/2017
Gun leather on the frontier was not designed for fast shooting.
For well over a century now a caricature of a cowboy dressed in batwing or woolly chaps, boots, Stetson and holstered six-gun slung low on the hip has been the stereotypical, symbolic, worldwide image of the United States. But in reality, a low-slung holster and belt were innovations most 19th-century working cowboys didn’t wear.
The history of the development of Old West gun leather has to be related in generalizations, because there were probably more than a few saddle makers and pistol-carrying wanderers and soldiers who dreamed up their own versions of holsters and gun belts before any of the popular styles became commonplace. Prior to Sam Colt’s 1830s development of the first dependable cap-and-ball revolver, the smaller single-shot flintlock and cap-and-ball pistols were usually stuck into a coat, vest or pants pocket, or the larger pistols were stuck into the waistband of the pants. Some pistols had a slender L-shaped hook on the left side of them to hook over the top of the pants or belt for carrying the gun. And the first “holsters” were nothing more than a piece of leather rolled and stitched into a“socket” shape through which to thrust the single-shot pistol for carrying on a belt.
The first holsters as we think of them today were a pair of leather pouches stitched on the opposite ends of a piece of leather, so that the holsters could be slung over the pommel of a saddle, with one holstered gun hanging on each side of the saddle. Somewhere along the way, the U.S. Army decided to put flaps on these holsters to better protect the pistols from water and dust. A few of these double flap holsters, known as “pommel holsters,” were even made for the giant-sized Walker Model Colt revolvers used during the Mexican War of 1847.....................................................