Hey guys and gals, I have a revolver that I inherited from my grandfather and I don't know a whole lot about it. On top of the barrel it says Model of 91 so I guess it's model of 1891? It also has no caliber designation so I don't know if it's a .38 S&W or a .32 cal. I'm guessing it's a single action based on some pics I've seen of the double actions. It has a very low 4 digit serial number that starts with a 9. I need help figuring out exactly what kind of gun it is (1st, 2nd, 3rd, or 4th model), date of manufacture, and approximate value. Any help is greatly appreciated. Thanks!