Even if Yamaha takes over Gibson, they would be stupid NOT to produce in the USA. I think more brands are owned by foreign companies than we know.
Lotus is a quintessential British car brand, but 51% Chinese. Aston Martin is - I think - owned by a consortium of European, Kuwaiti and Asian companies. Our Dutch truck brand DAF, which is as Dutch as tulips, wooden shoes, windmills and Rob van den Broek's criticism is owned by Paccar, which also has Peterbilt and Kenworth. So Gibson can be as US as it can be and still owned by Yamaha or any other company.