I think a plaque to commemorate the original geocaching site in Australia would be nice, but let's not pretend it is still the original cache.
At least it would be something to see when you do the virtual.
When I did the virtual I was a bit under impressed as it just isn't that original cache.
For what it's worth, I think it might make the virtual a bit more meaningful if it took you to a memorial.
Since we're talking about the first in Australia, not just the first in NSW, it probably isn't just a NSW issue and I'd contribute a few bucks.