Load tests are done on full batteries, but OP does not know if they are even close to full. An hydrometer would answer that.
The charging that was done on and off the past two years was a good thing, but as well, you should have charged them right up at 14.6ish volts every couple of months so they won't stratify.
Hard to say if they can be "recovered" from that, but maybe. You need to recharge them to full as they can get at 14.6 now and then do an "equalize" for a few hours at 15.5 or 16 volts, and see if the SG is up close to where it belongs with your hydrometer.