Not looking for period correct sights, just something that fits. With the 317, 63, and 60 still being made in 'kit gun' versions, modern J adjustable sights should be available. My 30-1 was built in 1969-70 by SN, so are there things about the newest J frames that would make the current production sights a problem on the older J? As long as the frame needs machining anyway, seems you could tailor the frame to whatever sight you find.

Patrick