Lyman makes a new tang sight, but it is junk! I bought one for a 1886 and it has a O-ring to hold your adjustment instead of a spring detent like the original. But is about 1/3 the price and quality of the MVA sights.

Montana Vintage Arms makes an exact reproduction of the Winchester Tang Sight. Marbles made a tang sight very similar also. I found one for a 92/94/Low Wall ( the 1886 and High Wall use the same sight) broken for $5 at a Antique Gun store. The only thing wrong was it had been reassembled with the elevation detent spring backwards. I fixed it in front of him, he offered my money back.

MVA makes Soule and Veneer sight repos too. His parts can be used to repairs the originals. Great people to work with. Call or get online for a catalog, then you'll be able to ask the correct questions! His sights come standard with the holes and screws for use with the factory tang screw holes. Custom spacing is available.

I use the modern Lyman on my modern High Wall and it works fine as long as you don't try to do repeatable adjustments. I had the Marble's on a Rossi 92 and would do all the repeatable adjustments you'd want!

I hope this helps you and your son enjoy you Low Wall and shooting together for years to come!

Ivan