IIRC, S&W instituted a manufacturing change in the mid/late '90's where ALL K/L/N-frame guns were made round-butt, with the same grip frame dimensions, therefore Pachmayr Pro-Compacs for the round-butt K-frame will fit the round-butt N-frame as long as the N-frame gun in question was made after the change. Furthermore, a popular modification before that time was to shave the grip frame down to duplicate round-butt K-frame dimensions for the express purpose of using K-frame grips.
If possible, take the gun to the store and try before you buy.