I don't think there's anything in the story that shows that the (fictional) Chinese didn't fake this right, but here's a thing that seems like it might be easy to get wrong and possible to detect:
I think you are
I'm in the north. I can be accompanied by violent crimes, a relative direction, or a body of fresh water.
I'm in the east. I can be accompanied by a wiild aanimal, a cardinal direction, or a place by the water.
I'm in the south. I can be accompanied by a financial transaction, an African religion or overflows of water.
I'm in the west. I ...
I believe Grandpa's complete itinerary is:
Explanation: As @El-Guest found, Grandpa is:
There are several possibilities for the 4th, 5th and 6th cities on the list if this is the only stipulation. However:
Since Grandpa has already visited the 3 cities mentioned just now...
There are only 3 such cities which fill the 4th slot on the list: