All I could find was the following info and it's for the 2011 50 shilling gold coin. 2012 may be different. If this info is correct I was wrong on my initial mintage number.
The mintage number I found is 10000 and all coins are proofs.
The coin came from the mint encapsulated. The coin has a plain edge, weights 1.24 grams, has a fineness of 99.9, and a diameter of 14mm.
Very cool, interesting coin. Hope this helps.