attached is a picture of a JD 813 plow that I found on the internet. The picture gives you a better understanding of what your plow looked like years ago.
it came with a gauge wheel on the right side as the old tractors that pulled this plow did not have depth control,
however, the rear gauge wheel looks bigger than yours, the rear wheel on yours looks more like the trail wheel on my old John Deere mounted corn picker (one row semi mounted)
per the info in the picture the plow was a 3x14