Agree with the above. I have a Ruger Vaquero Bisley 357 and it fits all regular SAA holsters I have including Hunter, Viking, Triple K, George Lawrence, plus a few I've made. The Bisley fits the one shown on my profile picture which I made for the accompanied Pietta Gambler Royal in 357.
Yes, it has a low wide hammer but any of those mfg holsters have adjustable hammer straps. Shouldn't be an issue unless the holster is super custom for Bisley only.