Over the past few centuries China used two monetary systems: the cash system and the dollar system. In the cash system, 1000 cash equals one tael, at least approximately, since actual conversion rates changed with time and location. In the dollar system, 10 cash equals one cent, and 100 cents equals one dollar.
The coin catalogs show that Fengtien Province minted various cash and dollar coins, but no tael coins were produced, except one. The single Fengtien tael was produced as a pattern, that is, a trial coin that never circulated. The Fengtien tael is known by its Krause Mischler designation KM-PnA15 and is dated 1903. There is only one known specimen.
It was major numismatic (coin collecting) news when PCGS, a respected coin service, authenticated, graded, and encapsulated the PnA15. You can read about it, with pictures of the famous coin, on CoinWeek. The coin is insured for $5 million US dollars. It is not over-insured.
Mark, you might have a previously unknown genuine PnA15, but I doubt it. (Wouldn't that be nice?) Instead you have one of the many known counterfeits of the famous coin. You can find these on Internet auction sites and in coin shops around the world. These fake coins are worth zero, or close to zero, so there is no need to insure you coin for $5 million.
If you go to the CoinWeek page and compare your coin to the genuine one, you will find many small differences. For the fake in our picture, there are two obvious differences: (1) the dragon image is mis-aligned, and (2) the annotation Fen-Tien is not hyphenated.
Thanks, Mark, for an interesting inquiry.