It does look like a Bone Button. I have a diamond shaped one in the lower left corner. I believe these were early settler items. The one I found came near an old Trading Post site that was located right in the middle of a huge Ft Ancient village. Several Glass Beads were found in the same area.
Grim that is nice looking box of stuff you have there. Drilled, bone, micro lithis, burin example on the big scraper. With all those banners you know what your looking for and at.