Wasn't the .1 Cas Silver the rarest produced, maybe version 1? I'm trying to remember if anyone else does.
Edit: Nevermind, it was the .5 Cas I was thinking of.
2012 had 8, 2014 37 and 2013 764. Technically the rarest Cas ever produced is the 10k LTC 1 of 1 made for Charlie Lee. Truth is no one knows for 100% sure about any of the mintages. Not sure Mike does himself.