I recently found and purchased the Colt Bisley shown in the attached photo. I know the collectors value is negatively affected by the modifications, but I don't care. It's beautiful and, appears to have been shot little, if ever. The serial number dates it to 1900, and the gun is pristine - not a turn mark on the cylinder and the bore is sharp and perfectly clean. Crisp and sharp rifling with no sign of wear or corrosion. And the grips are real ivory!
The big "problem" from a collector's standpoint is the vent rib. But I like the darn thing! While I don't know for sure, what little I can find out makes me think it was done by King's Gunsight Company. It has a nice adjustable front sight. And maybe you folks that know more can tell me for sure, but looks like the rear sight is aftermarket to me.
Another interesting thing is that the barrel is correctly marked for "Russian and S&W Special 44" (two lines), although the 44 Special was not introduced until 1908 (remember serial number dates to 1900) and Colt didn't chamber the Bisley for it until 1913 according to what I've read. I know it wasn't uncommon for frames to be unused for a number of years, so perhaps this revolver was built after Colt began chambering the 44 Special. Or perhaps the barrel was remarked and renickled by King's (or some other gunsmith)- after all the only physical modification required is lengthening the chambers in the cylinder.
At any rate all the work is first rate and the gun is a great shooter. And I bought it for less than the grips would cost now. No matter the collector value, I love it and am darn pleased........