Updated: Nov 23
The backside of a holster is covered with clues as to its maker, not least the maker's mark if any. Another of my blog posts covers the sewing of the belt loops, another covers construction clues about the eras, and this one focuses on the marks themselves with three PDFs combined into the one restored posting:
The oldest maker we know of was Main & Winchester, founded mid-19th century in California of all places. I say it that way because the Rocky Mountains blocked settlement past them until more than just a Pass was discovered early in that century; it was the RR completed at the end of the Civil War that opened the west. Until then the saddle makers simply piled up in the Territories at the base of Rockies on their Eastern sides.
Main & Winchester survived into the very, very beginning of the 20th century when it was bankrupted by its creditors, so to have a holster so-marked absolutely does not mean it was made in the 19th century. Virtually all mid- and late- 19th century gunleather was the product of the Civil War and carrying by civilians was delayed well past that war by a variety of factors. The 20th century is when citizens' gunleather 'happened' and post WWII is when it boomed. "Since the last War everyone wants to carry a pistol", said Heiser's factory super in 1951.
Gaylord (below) was the big Northern maker for the Civil War, refusing to sell to the South not least because Gaylord himself was a Republican. If your Gaylord-marked leather doesn't have red rot then it's not authentic! Because it was in this very era that American veg leather was plagued with it, 1850s-1900 and was not eradicated until the turn of the that century. And of course it m/b hand sewn because there were no harness machines until then either.
"Holstory -- Gunleather of the Twentieth Century -- the Second Edition" is available at www.holstory.com and is posted to you from inside the USA by the printer itself.