The walls were stained at one time As far as I know, pretty much everything in FL has reversed at one time or another... cept maybe Jug?
Ginnie has reversed significantly in its history, I recall a study of some wood shards they found in the cave which were a few hundred years old,placed there by a reversal.
The only reason Jug doesn't reverse is it would take the whole Ichetucknee river to flood,which doesn't happen much.