The simple answer is that all grip frames for Ruger Single Six, Blackhawk, Super Blackhawk, Bisley and Vaquero will either fit, or can be made to fit.
The older models, referred to as Three-Screw models, require a different grip frame than new models. All older Blackhawks had aluminum alloy grip frames. these can be replaced with the steel grip frame for the Old Army cap-and-ball Ruger. But a wider trigger is required. The old model Super Blackhawk trigger can be used, or an Old Army trigger if you can find one. Or, Dave Clements, Clements Custom Guns, makes a wide trigger that is superior to the original factory triggers.
On New Model Rugers, those with the transfer bar, the grip frames are interchangable. The Blackhawk or Super Blacckhawk can be converted to a Bisley but also requires a Bisley hammer and trigger. Conversely, the Bisley can be converted to Blackhawk in the same manner.
The New Model grip frame can be fitted to older three-screw models, but requires some fabrication to provide for the trigger return spring.
As to the brass grip frame from Brownells, there is some discussion on the Ruger Forum as to its worth. It requires considerable work to fit to the gun's frame, and to work it down to make the grips fit. Also, the grip locationg pin hole has to be plugged and redrilled to proper location.
This is my Ruger Blackhawk set up as a Bisley:
And, converted back to Blackhawk, with a steel grip frame:
And, two of my .45s with steel Super Blackhawk grip frames:
And, an old three-screw flat top fitted with an Old Army grip frame and Dave Clements wide trigger:
I got wordy again, but there it is.