Never seen one, they must have made a plate version of the air planters? All 800s I have seen were air with a single hopper for seed.
I would gues the plate parts are based on the 56 style and would have parts available from Case IH? You can find plates from Lincoln and other places.
Anyhow, if I see that right? JD made a plate version of the 7000 also, I've seen a couple of them, pretty rare too.
Any more, 400 to 800 planters were selling for a couple hundred bucks around here, but this is a different deal, don't know what to value it? Looks in nice shape, and with the fert.....