I mean what are the chances that a mythical creature, would be that close to an actual animal that was later discovered.. unless the ancient Chinese did their own fossil research!
They are actually not the same creature. (For a lot of Chinese culture the English-speaking world often come up with a familar item that's analogous to the Chinese item and add the word "Chinese" in front of it instead of calling it by its Chinese name.) Here's a more in-depth answer from previous thread.
I'm pretty sure the 17th century find was the first time it was recognized for what it actually was. People would have been finding all sorts of fossils and otherwise preserved bones (such as mammoth tusks) for essentially all of human history.