I just realized something peculiar as I was searching through NGC's census reports on the spectacular Xi-Shi Holding A Pearl medals. The brass and copper versions of the Xi-Shi are dated 2011 on the labels but the silver version is always dated 2012. Does anyone know why? I know that generally, bronze, copper, and brass versions are struck before the silver versions but I assumed that the dates would be all the same for a particular design regardless of the metal that particular design is struck in. Were the silver medals struck not in 2011 like the brass and copper? Here's the census for the brass: http://www.ngccoin.com/coin-census/...cna-xi-shi-holding-a-pearl-80mm-coinid-996236 Here's the census for the copper: http://www.ngccoin.com/coin-census/...a-copper-xi-shi-holding-a-pearl-coinid-411418 Here's the census for the silver: http://www.ngccoin.com/coin-census/...a-silver-xi-shi-holding-a-pearl-coinid-994614 How common / uncommon is it where the silver version strike is indicated with a different year than the other metals? And is it because the silver medals of the same design as the brass or copper are actually minted in a different year or is it an NGC mistake? .