1968 Two Cent Piece

Hi I'm new to this. When I was a kid, someone told me the 1968 Two Cent Piece (Aust.) was rare. Not really knowing whether this was true or not, I checked my change for it, and recall I managed to keep some, instead of spending them on Sunny Boys Razz's & Glugs. Fast forward about 40 years, and I found my childhood coin collection in an old cash box in my attic. Sure enough amongst other interesting things, the 2 cent coins were still there, all 10 of them. Interestingly one of the coins has some kind of manufacturing error on about 2mm of the the rim, both sides. When I look at the edge of the coin, I can see definite but small cracks, like the piece of copper used was imperfect. Considering the semi-rarity of the coin and the fact it has this minting error , would this perhaps increasing the rareness , would anyone know what this could be worth ? I see that ordinary circulated 2 cent coins go for a between just a few dollars to $10 depending on condition etc..

I also found a 1970 captain cook anniversary landing daily mirror medallion, the medallion is in excellent condition , although the original cardboard surround and plastic sleeve has seen better years. Any idea what it's worth ? My poor old Nan gave it to me when I was 9, apparently she went through many garbage bins to collect the xxx number of tokens to claim a medallion. (So there must have been many of them). I'll try to take a pic of both soon & post it here.