Ok so, my mom wants to get my dad a Smith and Wesson Model 13 for his birthday in January. Being the "gun guy" of the family (my dad, also being a "gun guy", but to a lesser extent) my mom asked me to look into it for her, which I have been dutifully doing. My question is, being unfamiliar with Smith and Wesson revolvers, what does the -'insert number here' mean? For example; Model 29-2, Model 13-3? I've tried googling it, but I really don't know how to word my question in order to get the response I want out of the search. I assume -'insert number here' means a different configuration of the model...?