Those trojans are about as a robust lead acid battery as one could buy.
But they are not immune form self discharge, and sitting undercharged will cause the sulfation to harden. and be extremely difficult to be driven back into the electrolyte.
Perhaps recharged properly, and then equalized their capacity could be returned to 80% or more of their original capacity, but if they were discharged when taken from service and never recharged, then they are likely only worth their weight in lead( pb)
If i were in the market and presented this opportuinty I would bring my hydrometer and voltmeter and a strong LED flashlight to shine down into the cells. I would bring my 40 amp charger and hook 2 of them in series and see how quickly voltage rose when 40 amps was applied and how quickly Specific gravity rose.
All these data points would give Clues to remaining capacity and potential recoverable capacity, but it would eb a guess and a proper recharge and extended equalization and then a 20 hour capacity test would heva to be performed to definitively say whether they were worth 100$ each.
it could go either way and without any sort of clue, one is entirely guessing that it will or will not be 200 dollars well spent.
200$ as you need two of them for 12V
