Hmmm - very odd. It looks like maybe they took 2 discs and bolted together with 3 pt bracket, but not sure how it would be hooked to tractor. Maybe there is a draw bar hitch hidden from view?
I have a similar set. Can't tell the exact size by the pic but looks to be missing some parts. Mine is of the same design but has 4 desperate weight boxes, 1 on each set of discs. It has 2 diagonal bars overlapping on each side and 2 in the middle, so you can change the angle of the discs, and a draw bar. Mine were made by Farmall.
I would venture to guess we're looking at the back of it. I had that thought at first, too, but then thought about it the other way and it seemed to look right. Could be wrong though.