My father in-law passed away and left me a Smith and Wesson 422 22LR. It is missing the rear sight. It has the 4 1/2 barrel. The way the slide looks I believe it is a target model. It has a long sight missing that is about half the length of the slide. I'm wondering if any one would know where to buy a factory sight. I would like to just make it stock. Thanks in advance for any help.