Is anyone familiar with the early Lyman 35 peep sight for Mausers? I recently acquired a nice rifle with one installed and it's missing the aperture. The windage adjustable aperture base is still intact but no internal parts are present. The sight base is otherwise in great shape.

I'm finding that the 35 is a fairly rare sight, is there a more common sight that I could use for parts, or are parts available with other sources?