In general if they don't like where they are placed they will move (or try to). The GSP as far as I know are not a stinging coral so as long as the clam seems happy I wouldn't move it. The only thing I would watch out for is the GSP growing on the clam shell and possibly irritating the mantle as GSP can be quite an aggressive grower.
Wow nice clam the pvc is a good idea I like the way he looks in the gsp just was worried about it bothering him. Right now the gsp is touching him on the lower part of the mantle but he seems to not be bothered