I notice that the obverse of the coin shows a 1Ag5 prefix -- if I'm not mistaken, there are 1Ag6 silver+gold 1oz coins out there. Anyone able to verify?
Production of 1BTC coins starts from the beginning of the set (1Ag1, 1Ag2, 1Ag3, etc.)
Production of 0.5BTC coins starts from "a" (1Aga, 1Agb, 1Agc, etc.)
Production of 0.1BTC coins starts in reverse from "z" (1Agz, 1Agy, 1Agx, etc.)
From Casascius.
I can verify that there ARE Gold/Silver coins with the 1Ag6 batch - I have some and am pretty certain it is the last batch produced