had one
I had one of those, the grips are unique, and you will be hard pressed to find anything that will fit on that frame except the factory service grip shown. My understanding was that Ruger then modified the frame in later production, , and the grip people got on board and began to make options. I kept the skimpy service grips on mine, and looked for options and never found any,....back in the day.
Mine would shoot, and the SA trigger pull was just out of this world fantastic. DA only acceptable. Pet load was 158 LSWC to 1000 fps. Carried that old revolver a long time as a personal duty gun, and as a woods roamer.....then as the agency went to autos.....traded the "Six" for a Blackhawk. Had to have a hogleg.