No seals on Seal Rocks, alas. (Or sea lions now, for that matter.) But back in the day when the rocks were covered with pinnipeds 'slithering around like maggots on pudding,' the creatures were all either Steller's sea lions (Eumetopias jubatus) and California sea lions (Zalophus californianus).
But no seals.
So then, JB persists, why are they called Seal Rocks?
Apparently early Yankee visitors to Point Lobos didn't know the difference between the two. They didn't care about visible ears or opposable flippers or other defining features that separated the species. If a critter was shaped like a seal and moved like a seal, then tarnation it WAS a seal.