These will work on a K, L or N frame S&W. Prices are ftf in the Denton/Lewisville area, I can toss them in the mail for a couple of bucks more. PM any questions.
Extended thumb latch of unknown brand, aluminum, works fine, just doesn't fit me. $15
Fixed rear sight, replaces the adjustable sight for easier concealed carry. $90 at Brownells, get it here for $50.
B-Square scope mount, replaces adjustable rear sight. All hardware is there. $20.