I still would like to think that it is struck over a 1/10 oz. gold.

Wouldn't
that be fabulous?
Almost certainly and most probably isn't, however.
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I have an antoninianus of Postumus that is gold plated.
The binios of that period are the real gold coins, and I have only found examples of those on Google Images.
As far as I know, not even Wildwinds shows an example.
In all of my collecting experience of many decades, I have no knowledge that a binio has ever come up for auction, anywhere in the World. However, they do actually exist.
Google Images 'binio' to find out more if you wish.