Though not marked, this appears to be a Chic Gaylord Treasury Thunderbolt.
The interesting feature is the leather piece situated in the bottom portion of the belt loop.
This slightly forces the bottom of the holster away from the body while slightly forcing the upper part of the gun into the body. This prevents the gun from “hanging” or flopping away from the body at the uppermost part.
I’ve tried this with a Chiefs Special and it’s most effective in keeping the gun in tight against the body.
Perhaps Red Nichols can opine on the maker based on stitching?
