Yes, they fit with room to spare. I keep several vests and ropes on top of them. My SS is a '95 so I don't have any factory ballast. I don't know about the newer 210's with the factory ballast.
However, I've been looking at having some custom sacs made that would totally fill the space. I need a little more weight for surfing and if I had a big rectangular sac made for the starboard side it would be just right.