I got 30# of Florida rock from Gulf-View a few weeks ago. It was the less expensive "coralline" version. The life on it is unbelieveable compared to any Indo-Pacific rock. Sponges, tunicates, several species of bivalves, several miscellaneous snails, limpets, hydroids, a
red brittle star, barnacles, several cup corals, fan worms, a variety of other types of worms, several species of algae, and some things I don't recognize. Also a few small crabs and a pair of Aiptasia, so watch out!
Since then the barnacles and the larger sponges have died. However, even though the tank has cycled in the mean time, most of the life appears to hanging in there.
On the other hand, Florida rocks are basically shaped like rocks, not old pieces of coral.