1899 Liberty Eagle (Mounted)

I apologise if this is in the wrong place and/or considered inappropriate in a coin collecting community.
Discovered while clearing my late aunt's house, a USA 10 dollar dated 1899 in a mount with a detachable pocketwatch chain.
My knowledge of the coin is from 15 minutes on Google but I am puzzled by the stock images hence this query.
The Liberty head is aligned with the centre of the mount but flip the coin/mount over and the eagle is upside down with respect to the head. Are they all like this please? I don't want to sell something that is counterfeit.
The watch chain including 'T' piece is hallmarked and stamped 625.
The mount/clasp is also hallmarked and stamped 375. All mounting points to the coin are intact.
The coin faces have tiny scratches (consistent with use and age I guess).
The coin edge serrations visible either side of the mount are present with no evidence it has been dropped.
There is no mint mark underneath the eagle.
The coin/mount/clasp weigh 20g and together with chain weighs 56g (wife's digital kitchen scales).
Little provenance except found among WW1 medals and badges including some US and Canadian items that along with the coin were possibly traded among the soldiers.
Any help will be appreciated.