Quoted:
Open carry is legal statewide, with NO allowances for local ordinances to override that. In other words, even if you live in Jackson, and have to deal with an asshole for a cop, open carry is legal regardless of what he THINKS to the contrary. Period, end of story.
Yellowstone is a National Park, so the feds DO overrule Wyoming's rule there.
Concealed carry is legal, statewide, only with a permit. You CAN open carry in a bar, but concealed carry, even with a permit, is illegal. It's poor judgement to open carry, even in smaller towns, in the bars, unless you are a well-known and -liked local, because some dumbshit tourist will start shit with you, just because he can.
Depending on where you are in the state, open carry is actually pretty common in some areas. Crook and Weston Counties both have a LOT of people, both townies and ranch-working cowboys, who open carry 24/7. Sublette County, and other less tourist-centric areas as well. Anywhere there are still a LOT of working ranches, you'll see quite a few guys open carry, although Glocks and XDs may be pretty rare (I've seen lots of the de riguer SA revolvers, and more than a few 1911s).
When I moved back into the state, I sat down with a local attorney, then walked in and visited with the county sheriff for over an hour to discuss this. Both gave me this information, almost verbatim.
Open carry in a privately owned establishment who's owner doesn't want open carry in his place of business and see how far you get with the local cops.
Ostentatious display and open carry, while on the surface the same thing to some, aren't the same thing. Flash that hogleg and smart off to a Laramie cop, for instance, and see what happens. (Laramie, in Albany county, one of two blue counties in the state)
As for what sorts of pistols are carried, I haven't seen a revolver on anybody's hip outside of Frontier Days in ten years. Glocks, Sigs, S&Ws, the odd 1911.
But, hell, don't pay no mind to me, I just live here.