They have the copyright to the specific design I'm sure. Similar but different designs on the other hand, no.
Unless our friend here sells them under a name that breached GW copyrights or literally copy & pasted the design from some existing product into jewellery, it would be fine. Having a crossbar and skull on the letter I probably isn't specific enough for a copyright claim, and the design could be changed quite easily while retaining the general look even if it is.