As mentioned there were a variety of sights used on the old Stevens. Marbles and Lyman seem to be the most common. However, be warned, check the dimensions of those dovetails. Many of the old Stevens have over sized dovetails, more like 7/16", not the standard 3/8". I have a model 44 in 32-20 that uses the 7/16" front sight base. The tang sight screws are also encountered in two sizes. When I installed a Lyman tang sight this past month I had to re tap the mounting holes to accept the larger screws that came with the sight.

John