I believe China started buying Buicks during the 1910's.
GM was just Buick back in 1908 when William Durant formed GM. Durant bought Buick in 1904. He quickly purchased other makers post 1908 in this order - Oldsmobile, Cadillac, Oakland (which became Pontiac), and then Chevrolet.
We have a 1922 Buick roadster that is a time capsule. We're the second family to own it.