How to Attach Plow Handles?

I am trying to restore a No. 30 Syracuse walking plow to original condition. The handles are gone and I am baffled as to how they were anchored below the obvious place between the shear and moldboard. In the back of the plow is a pair of half-round mounting slots, one on each side that look like they held a rod in place. I surmise that the handles were somehow anchored there as well. It looks like there must have been a mating part(s) to the half-round brackets. If you have any information on this plow and how to correctly attach handles, I would be grateful for pointers.

This plow has an interesting story. It has been continuously owned by one family, passed from grandfather to son to grandson (who is now 74). In his youth, the son hooked the plow on a root in the field and tried to get the horses to yank it out sideways, rather than back the horses and drag the plow backward, breaking the beam. The grandfather welded it back together in a visible but rather elegant repair and continued to use it. When welders of today see the repair job, they marvel at it and wonder how it was done, because evidently this type of repair is very difficult to accomplish. The grandson wishes to restore the plow for his daughter and possibly for her new son, should he decide he has an interest in horses someday.