This is a common date through Gem levels and is known as high as at least MS68, though at that lofty level they are quite rare. Overall, the 1878-S has always been regarded as one of the more widely available pieces and has been sold in bag quantities through into at least the mid 1960s. PLs and DMPLs are understandably scarcer but are frequently encountered through MS65 levels with a few rare pieces touching as high as MS68.