It's hard to tell from a pic of the skeleton, but the hammer looks more mad, than dead. It could be a light acclimation issue, or it could be an ALK
issue, what are the water parameters? What is flow like around the hammer? It will open best in a low flow, enough to lift and sway the polyps, not streaming in the wind.
As for the clam, I can't check my book, but it seems I remember smaller derasas do use byssal filliments and only stop useing them after they reach a certain size. The problem there, is if the clam was attatched at the LFS
to more than just sand, they could have ripped the byssal gland out of the clam when they removed it from the aquarium. This is almost always fatal.