According to a blurb posted above, it's "Carbine" Williams. On the counter is what looks like a pile of Great Western SA's.On the left side- That almost looks like Elmer - Cigar and Hat.
According to the advertising put out at the time, both .38 Special and .357 Magnum could be fired through one. You may want to take a look at this thread: https://smith-wessonforum.com/firea...ve-great-western-arms-thread-ill-start.html?hSo if I came across one of the .357 Atomic's would a .357 magnum be fine to shoot in it? I'm curious and might begin a hunt for one of these on my travels.