I have a Marlin 39A that I got new in 1963. I mounted a Redfield receiver sight on it and have seen no reason to change it. 15 years ago I found a very nice Mountie, made in ’69, and used very little. The Redfield sight is long gone, so I mounted a Williams FP. It works well, but I also have a Winchester 9422. It isn’t drilled and tapped for a receiver sight, but a Skinner Sight fits very nicely on the grooved receiver. I think I may like it the best of the bunch.
I also don’t care for a bead front sight. I think it covers too much of the target. I have mounted black, serrated ramp front sights on most of my iron sighted rifles.