I have a 38 special with a 4" barrel. It's a 4 screw hand ejectors. Can't find a model no. on it but think it is a mod. 10. The no's I found on it if they help are, B391304, and 11764. The S&W stamp is on the cyl. in-lock side. I wanted to know how old this gun is and what it's worth may be?