yes if you break down the sulfation the specific gravity will go through the roof with the new electrolyte being in there.
i would suggest you drain the electrolyte, fill the cells with fresh distilled water
and put them on a good stiff charge for several hours, maybe even a few days.
keeping an eye to not overheat them and take frequent specific gravity readings of the water,, over time as the sulfation breaks down the specific gravity of the water will rise and then plateau.
after it rises to as high as you can get it, drain the battery again and put in the new electrolyte.
if you don't do this and leave the new electrolyte in there, if the sulfation does break down the acid will be so strong it will eat up your plates in an agressive manner.
bob g
