Not a ery good picture of the sight. A better view would hlep folks ID what ya got.
Robert
The fact of the matter is folks, especially the folks here, won't need much help identifying the sight. That's because Bob Neal (He of "Neal & Jinks" fame) and a legion of helpers have already done that---along with identifying damn near every other sight on ("damn near" again) every other (target grade) gun S&W ever made! Then Bob wrote an article about it. The article is titled The Evolution Of Smith & Wesson Target Sights (the ONLY comprehensive treatment of the topic ever done)---------AND there's a complete copy of that article available here on this forum---wherever such things are found---and however such things are found---which is beyond my store of knowledge--thanks to an expert and devoted staff who tended to such irritations on my behalf whenever such was necessary. Alas, my current expert and devoted staff consists of two cats---both of whom are smart enough not to go anywhere near such undertakings!
The article was a PRODIGIOUS undertaking, based upon the size of his research file which now resides in my bookcase. Once you find the article, go to the second installment, that treating with rear sights, and have a look at Designs 16, 17, and 13 (depending on the age of the gun)----------and VIOLA!!
All that's the easy part! Next comes what I suspect will be the daunting task of finding such a sight-----or even a donor gun. I say "daunting" based upon my 60 some odd years of tromping around here there and yonder looking on tables and under rocks for S&W target guns. Every once in awhile, I came across a pre-war Kit Gun----not often, but every once in awhile----pretty little things. One thing I did look at was the sights---of course having become a collector of target guns, one becomes a sight junkie---pretty much automatically-----and he ALWAYS looks at the sights!!
And speaking of here there and yonder, I recall going to the Las Vegas Winter Show NINE years in a row---and ending up with ONE gun to show for it! THAT borders on embarrassing!! Actually, it doesn't border on anything besides the fact I must be a slow learner!
It occurs to me you'll have better luck finding the article than the sight.
Ralph Tremaine
And having now looked at the recent pictures, the sight looks to be what once was Design 13. And given that educated guess, it can be confirmed by removing the sight assembly (assuming it, in its current state, can be removed) to confirm the presence of a horizontal slot milled in the frame (where there was, once upon a time, a flanged elevation adjusting screw with its flange riding in the slot). Needless to say, one MUST have that screw in order for a replacement sight to function---------or be VERY GOOD friends with the folks at a VERY GOOD machine shop to make such a little beast---at what might very well be a cost exceeding the cost of the gun. (!!)