I'm not sure if this is the correct place to post this. I just aquired a S&W 357 mag revolver with a 4" barrel model 58-1 Does anyone know much about this handgun, like when it was made, and how much it might be worth, it is in real nice shape, it is blued, and has a different grip on it. the grip is either plastic or ivory with a naked lady on each side. How can tell if it is plastic or ivory ?