This thread is a coincidence for me because a couple of hours ago I called Cylinder and Slide and ordered a fiber optic front sight for my 27-3. The factory sight on that gun (ramp, plastic insert) is an integral part of the barrel rib so C & S is going to remove it and then cut a dovetail into the rib so that a fiber optic sight can be pinned into place. I'd previously called Smith about ordering the work from them and the person I spoke to there said that they no longer did that work on older revolvers because they could not guarantee that the barrel wouldn't be damaged in the process and that they had no replacement barrels for the 27s. However, I have a friend who spoke with someone else at Smith who told him that they would do the work. Go figure. In any event, Cylinder and Slide has my order.
I'm going to have the ramp sight replaced with a Patridge-style fiber optic sight. For an additional small fee C & S will regulate the gun for me with the ammo of my choice. I'm also ordering an action job from them while I'm at it. I'm pretty excited about this project. My favorite shooter is another N-frame, my 625JM, and I have installed a fiber optic front sight on that one with great success.