Some good sleuthing ... kudos !
The watering valve was a great thought, and the plow part nailed it.
Great insight and research ... it's nice when it all comes together so well !
Great I.d. and fast to. When I was a small kid my uncle would plow with those on it. He plowed with a mule, he let me hold on to the metal cross bar brace below the handles , I would walk along with him,those were the good old days.