These were NCLT (Non Circulating Legal Tender), I think the US calls them NIFC? Usually only available from Coin Stores/Sellers now.
There were 4 different Mint Marks for them B (Brisbane), C (Canberra), S (Sydney), & M (Melbourne), from both the Portable Press and the main Press at Canberra, so there are 8 slightly different coins.
Unfortunately, I have 1 of each type & no spares. I know someone who may let me have a few though, so I'll ask the question & let you know if there's any available.