It looks like it may be homemade...is that possible. The John Deere offset we had when I was growing up on the farm in the 1950's was much heavier than this, and the adjustment parts were much more solid looking than this one. You pulled a rope and backed up and the two gangs would line up one behind the other so we could pull it to the field, and actually we pulled it down the sand roads in Southcentral Kansas from field to field. My Dad was the first farmer in our community to use this instead of a plow, and the land owner once told him, "You know all the farmers around here think you are nuts to work your fields like you do, but I'm making more money off your farm than any of the others I own."
I actually made me a four foot ofset disk that I pull behind my Kubota. It works just like the one in the picture.
KubotaEd