I orignally posted this mystery factory back in February. I recieved the answer to the mystery today by e-mail. Kevin who is an avid Buick historian offered this answer:
The photo is not from Detroit but rather from Flint. It shows what
was built as the W. F. Stewart Body Company factory on the southeast
corner of Industrial Avenue and Hamilton Avenue. The building of which
you can just see a window on the left is Weston-Mott, and the small office
building just to the right of that is the main office of the Buick Motor
Company. If I’m correct, this photo dates to around 1913, when other
panoramic photos were taken at the complex. Also, that particular old
Buick office building was built around 1906 and demolished/replaced around
1917.