If you're not hung up on getting an exact replacement in a Marlin envelope, you can do better than that. Never have liked the factory rear sights, look like something off a BB gun. Brownell's will have a Marble's replacement that folds down, should you want a scope or receiver sight sometime, also has your choice of notch types. They also have the Williams line of rear replacements, I've got a green fiber optic rear on one of mine. No hammer needed to install or adjust for windage, it slips in and has a lock screw, also screw adjustment for elevation. Or you can get the current rendition of a BB gun sight under the Marlin/Remlington section. Got to have better eyes than mine to make that work, though.