That South Australia is very similar in design to a Nova Scotia #8.
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There was a discussion on another thread about this design being used for a Tasmanian stamp, but I think we have the real 'copy' here.
http://goscf.com/t/19284&SearchTerms=nova,scotia,8It's uncanny. Like Patty Duke and her identical cousin (you have to be over 50 to get that one
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)