I'm certain it's genuine. If you can take a photo of the edge, that would tell a lot more.
Despite the chopmark and reverse damage, this is still a very popular coin. I would price it easily in the 100 dollar mark. (If genuine)
Some scarce coins do come from various countries. I'm not surprised if it's from a deserted town in middle of no where in Australia. Afterall, migrants went everywhere.
My partial coin collection http://www.omnicoin.com/collection/gxseries
My numismatics articles and collection: http://www.gxseries.com/numis/numis_index.htm
Regularly updated at least once a month.