Howdy we stock and sel a lot of grips for single action revolvers. Here is the answer....
The Taurus Gaucho is a Colt Single Action Army clone and will take replacement grips for the SAA. However, most SAA's and clones have variances in the grip frames due to the way they are manufactured including filing. Therefore, almost all of the grips we sell for the SAA have to be hand fitted by the customer or by the grip manufacturer. The same would apply for the Taurus Gaucho. The grips are all manufactured to the same dimensions... it is the grip frames that run you into trouble.
Conversely since Rugers are cast and then polished, meaning little if any filing is needed, the grip frames tend to be fairly consistent and grips usually fit acceptably with no fitting. The SAA and Rugers have diiferent shaped frames and are not interchangeable. Also, Rugers have differnet grips frames based on when the gun was made.