Howdy
'Pinched frame' refers to the rear sight on very early First Generation Colts and some replicas.
This is why they were called 'pinched frames'.
Some modern replicas are made to resemble the original pinched frame.
Ruger Vaqueros do not have what could be called a pinched frame sight. The rear sight on a Vaquero is pretty much the same as the rear sight on a 2nd Generation Colt. Here is the rear sight on one of my New Vaqueros. It is pretty much the same as the rear sight on an 'original model' Vaquero.
The sight picture with the old pinched frames was a very tiny V groove. The Vaqueros and modern Colts have a nice wide square bottomed slot, and the material around the slot has been cleared away to make it easier to see.
As stated, the Bisley Vaquero is not really quite the same as the original Colt Bisley grip.
Here is the Ruger version of the Bisley grip.
Here is an original Bisley Colt. The differences are obvious. The Colt Bisley shape swept much more forward than the Ruger version.
Bisley Rugers do not seem to me to be as prevalent these days as a few years ago. More shooters seem to be going to the traditional 'plow handle' grip.
I did own a Ruger Bisley Vaquero for a short while. I eventually sold it though because I did not care for it. The Bisley grip is a bit longer than the standard grip, and allows the shooter to fit his entire hand onto it. I discovered that I much prefer to hold a single action revolver with my pinky curled under the grip, rather than trying to cram my entire hand onto the grip. This allows the pistol to rotate a bit in my hand in recoil. I much prefer that to trying to cram my entire hand onto the grip.
Before you spend any money on a revolver, make every effort to try shooting both types. Some prefer one, some prefer the other.