Yes, they can be very difficult to replace if you don't have the assy.

I worked very hard to locate one a couple of years ago.
Since then I've squirrled away all the spare sight parts I've come across.

Hammer noses (hammer mounted firing pins) used to be hard to come by too, so I also horded them.
Now Powers Custom makes great hammer noses.

Someday, someone will make replacement sights, until then, fixed sight revolvers rule the world.

Brownell's had them for sale at one time. Don't know if they have one for an L frame in stock at any given time. Also Simmons in Olathe Kansas was an official S&W repair station when I was working there. I use to go there and buy sight parts from them. Give them a call.

Unless your customer really needs and/or wants an adjustable sight, Brownells has a fixed sight that fits into the recess. I know it was made for the K-frame, and I suspect for the L-frame too.

The fixed rear sight that Brownells sells is about $100 and I'm Cheap Charlie. So, on hard-use guns, I file the elevation stud down so that the sight will crank down into hard contact with the frame, zero it for windage, and file down the front sight to zero the gun with my "using" load. Then I goop the sight up good with Locktite to make sure it never gets moved off zero. Point being, adjusto sights aren't really necessary on most handguns.

Lee's Gun Parts
Irving, TX
(972) 790-0773
He's at the store Tues - Thurs. Other than that he's out buying parts inventories at out of business gun stores or setting up at Gun Shows.

.

--
Sincerely,

Hobie