Not 100% true about the ways of the theater. My sister was a theater design major in collage and for the last 10 years she had moved on and continued to run the department as well as work with larger theaters and movie production.
I've been involved with prop rental for some time (most recently all of the US and Russian combat swimmers diving equipment that was CGI modelled by Treyarch for "Call of Duty, Black Ops I and II" were provided by me, via the prop-house "Sacred Sword" that does things like equip Saving Private Ryan. Trust me.. the prop house collections are huge and are very interesting to poke thru.
What they spend on rentals when they need something specialized like I provide is... well....
What you say is true to a degree now. The cited revolvers (above) are obviously antique... and this was not true then.
I respectfully submit that more information in the form of detailed photos of features and markings are the sole source of data needed for further clarification.