The original stone is on the move to St.Fagan's Open Air Museum, to be part of a new exhibition, here is a description of its removal....
http://www.museumwales.ac.uk/blog/2007-09-27/Moving-the-Bryn-Celli-Ddu-stone
What worried me reading Culture24 was that they seem to say it was the tomb being removed, but no after further research it was only the stone...