I worked on the line at the Framingham GM B-O-P plant in 1972.
The plant looked exactly like the pictures shown. I believe that GM used the same design in all thier plants.
Supervisors were required to wear white shirts and ties.
All workers had to wear coveralls at every job.
The plant was noisy, hot, and somewhat dirty.
But, the smell of rubber, metal, and new paint was heavenly.....