I enjoyed reading your interesting comments in an earlier thread about this.
I had a little handbook of American Indian sign language and was visiting the Smithsonian's Museum of American History when they had an exhibition of Shang Dynasty characters on display.
I found my sign language handbook told me what the Shang Dynasty characters were saying.
Obviously Chinese people had some connection to the first folks into America with a full fledged sign language ~ and that's the Na Dene ~ but given the Na Dene presence here BEFORE the Shang characters were invented, that meant that these guys were actually going back and forth from Central China to North America.
Eventually some Chinese anthropoligist will discover signs of American visitors in China several thousand years back.