Just an added comment to be sure the OP understands that that holster is most likely much older than 1940. Brass flap closures, combined with the embossing and style was popular from 1870 to 1910. I think many early small holsters had a flat brass button style closure, while the brass ball military type closure were found in small holsters later in the 1800s.
From what I have observed, many early flap holsters for pocket revolvers were made of quite thin leather, while those made by around the 1890s and later seem to mostly be made of heavier leather like the OPs. So those catalog pages would also be my guess as to the age of your revolver, from the late 1890s and early 1900s.
I bought one Model 1 1/2 with what was stated as an original holster. Not sure, but the fit was good enough and that holster would have fit any Model 1 1/2. I do know that these holsters were made to fit several styles of revolvers and if one looks at this one, it would fit a revolver with a trigger guard as well, so while it might be original to this gun, it does not mean it was only made for a Model 1 1/2. To determine the type of revolver that was kept in an old holster, one must do some detective work. Checking the impressions on the leather may show what model revolver it was used for. If you look at the ejector rod on the Model 1 1/2, you can see the impression on the holster, meaning the revolver was in there a very long time.
I am adding some hints in red that this particular holster probably held a Model 1 1/2 for a very long time.