Hi All. Thanks for the information on the Pre-27. Mine is also 3-1/2" "S" prefix and 5 digit serial #. Purchased used in 1972. Was told it was an Alabama State Trooper's gun. Will the value be affected by refinishing the original rosewood target grips? They have taken some abuse and wear over the years. And yes, I plan to get the S&W letter. Thanks for your input. You guys know a lot more than I do about S&W.