Here's my factory Nickel-Plated 15-3. It's a working gun, so I did not want to damage the Walnut stocks and use these, and they fit my fit my short meathooks better anyway!
Here is a model 15 that was improperly stored and has three or four pits but other than that it looks and shoots great. I bought it cheap and was very pleased with it.
4 screw pre-15 from 1956, with diamond magnas numbered to the gun and a S&W branded grip adapter. (Later targets added from grip box to fit my big mits!):