My father has several K frame S&W revolvers and most are model 10. He has one model 10 I've never seen before. It's a model 10 with skinny 5" barrel and rounded butt. According to my father he acquired that revolver around 1959 or 1960 from one of his customer...but he could be wrong as his memory is not so good now. How common or rare is this model 10? I've seen many 5" skinny barrel models and I've seen many with round butt but I've never seen one with 5" skinny barrel and round butt.