I don't know who made the frame; it's not mine. I can only assume the bosses are threaded. The frame has sport touring geometry, three pairs of bottle bosses, three top tube cable guides and no other braze-ons for racks or the like.

One would think they were fender bosses, but you only need one and two will be of no help in eliminating a rattle. It would offer a bit more rigidity, but most fenders have a rounded profile, so I'm not seeing how these two bosses make any sense for fender mounting.