I was thinking about having a night sight installed on my 3" Model 10-8. There's not a whole lot of info about installing one on a fixed sight K frame other than XS sights telling me they don't offer one for that configuration. It can be done though, here's a 3" 65 with a dovetailed replacement sight...
Novak?s Custom Smith & Wesson 65 Half-Fitz Special | Shooting Illustrated