In 2006, the Royal Australian Mint accidentally issued a number of proof sets with a 2005-dated dollar coin. The reverse of this coin bore the standard Kangaroo design (known as the “mob of ‘roos”). Because the proof dollar coins issued in 2005 carry the End of World War II design, the 2005 proof dollar coin with the Mob of Roos design was never meant to exist. Downies originally discovered twenty of these coins in their allocation of 2006 proof sets, and Colonial Coins discovered a small number shortly after. In his price guide, Greg McDonald suggests that fewer than forty examples of this coin exist, making the coin one of the rarest decimal issues to date.
Up until recently, PCGS had not yet certified this rarity, as many collectors preferred to keep the proof sets, in which the coins are housed, intact. However, because it is the dollar coin that is valuable and not the set itself, one collector decided to send the coin over to PCGS to see how it graded. That coin, graded PCGS PR69DCAM, is photographed below.