FWIW, I bought my 431 used. It was made in 1992 and is a 4" barreled, square butt. The frame has a large pin for the grips. The grips that came on it are Uncle Mike's rubber grips. The Uncle Mike's grips have "59009 Fits Lg. Frame Taurus post 89" on their insides. I found a set of wood grips being sold as for a large frame Taurus on Ebay and they fit quiet nicely on my gun.