Seems George headed out to LA around 1970 but didn't seem to work for Motown much at all.
He was in a jazz outfit, the Ernie Watts Encounter that cut a lot of jazzy versions of Motown songs. He then pulled together the George Bohanon Brass & Reeds Section who did studio work. With them & in his own right he worked with the likes of Lamont Dozier, McKinley Jackson, Paul Riser & Angelo Bond + on many other jazz, soul & pop studio sessions. He was then a member of recording groups Brass Fever & then Karma. By the 80's, he was out on the road backing the likes of Ry Cooder.
Seems strange that after he led the last real incarnation of the touring Motown Revue Band, he was largely ignored by the company after the LA move happened [[though he did work on Diana Ross, Willie Hutch, Originals, Temptations & Stevie Wonder sessions).