I agree with Margaret. I might be risking my reputation as a historian here, and I'm sorry, James, but I don't think it is that old. It's in the detail
Getting your picture taken in the late 19th-early 20th century was rather expensive. Even though they look posh, the clothes don't fit them. The lady's hairstyle is too short, as Margaret points out, the fashion was long hair, no matter your age. Another thing about the lady, she would never hold her fan like that. Either it should be closed, or if open, she would never touch anything but the handle.
If you look at the men's clothes, it is too big for them. Rich people wouldn't have allowed that lack of fashion judgement
Another thing, and that might be far fetched, is the ways the guns are pointing. One of the men has to be right-handed, the other left-handed, otherwise the guns would point the same way - you know, when you reach for it. As it is now it looks staged, like the guns have to point in different directions in order to "frame" the woman in the centre.
But I do like the Cavalier