I don't think cussing on its own is anachronistic, just the use of "fvck." Of course, I'm not an expert on the Old West, but I just think of this more as a modern favorite. My thought was that back then they would have had different "preferred words."
The constant use of fvck just seemed to take me out of the context, like I was just watching a bunch of modern actors in dirty vintage clothing playing dress up. I suppose I can give it another shot.
