It is a gamble, but you need to hedge your risks. If you have the money to risk, and get a $40k machine, for $8k, that's a pretty healthy margin to fix what need to be fixed, and resell for $25k. I just don't know enough about the modern emissions stuff to say on that front, and if these specific models are easily deleted. Mechanically, gears can absolutely take some water and rust, and be freed up, and run many years, just fine. The unassembled ones, I worry that they may not have had fluids, and then held water for 9 months, without getting drained. Wiring, computer, and emissions are all at risk; even if mechanically its fine.
I would hazard to guess, if you bought 10 of them; 2 or 3 would be 100% fine; 1 or 2 would be broken down for parts; and the rest would be in the middle. You would probably make money on the whole; but buying a single one, you dont want that 10-20% chance of a near total loss.
I also would guess a fair number of machines have been half under water, and you would never know.
Also, depends on the purchasers abilities and time to fix, vs paying someone $120+/hour to make repairs.