S&W recently did a similar barrel option. About two years ago they offered the M41 "optics barrel". These were cut down 7" barrels and included the scope rail mounted.
The problem I saw was they were over priced but the even bigger problem was S&W wanted you to send them your 41 to have the optics barrel fitted. So now add another $60.00 for UPS Next Day Air rip-off.
So if they do it again they will require your M41 be sent in for fitting.