The GRIP frame is different but it's very unlikely the Bisley Stampede primary frame (also known as the "cylinder frame") is different than either the regular Stampede or the Marshal.
Certainly the Colt Bisley primary frame was the same as the SAA...
As to your question, yeah, should fit just fine. The problem though is going to be scoring the parts. At a minimum they'll likely be shipping out of Italy and worst case they'll consider that a "gunsmith install only" part for liability reasons.
Ruger hammers of all types can be had at Brownell's, which is where the SBH hammer on my New Vaq came from.