I noticed this a couple years ago and thought I'd share it here. Has anyone ever seen the movie "The Sea Wolves" with Gregory Peck and Roger Moore? It was released in 1980. Here are a few screen shots from the movie you might find interesting.
Notice Gregory Peck's holster here:
Now I know it isn't correct, but it's real close. Maybe Indy's was patterned after this one.
Peck's holster is a traditional revolver holster and has no connection to the Hi-Power. Moore as the British Officer seems to have a left-handed revolver holster, maybe a canvas one for a Webley? It's much too long for a Hi-Power. Out of uniform, Moore is definitely brandishing a Hi-Power, probably an Inglis, but we don't see what he was carrying it in.
I apologize for not clarifying. The Hi Power has nothing to do with the holsters they are wearing. Roger Moore's character took it off of a would-be assassin. I'm not sure about Peck, but Moore's weapon of choice was a K-frame S&W in the movie. I just thought there might be an Indy connection. Moore's holster looks like the traditional Webley and Peck's looks more like the inspiration for the Raiders holster.
Nice research and belt/holster in the pics. I was just discussing the Sam Brown belt strap in the concept holster/Steranko painting thread. The strap was good enough for Concept Indy!