https://thegreatmodel8.net/

I'm pretty pleased with the condition of this Model 8. It has lots of character, but no grave defects and a very good bore. As it was manufactured early in 1923, it will be a century old in a month or two and I might have to hold a birthday celebration. I don't recall having seen this particular two-leaf folding sight on any of the three prior Model 8s I have owned, but I like it, as I believe it will be able to "get out of the way of the Marble's aperture rear.

She's a beaut!!

I have a similar one and it's my favorite.

I have one marked 30-30 Remington with the same flip down rear sight. My sight is not as nice as your's and it is no longer tight, that is, it flips up and down between the two on it's own.