John spent some time at Chevrolet Final Assembly at Norwood. He related that Chevrolet employees were not welcome to snoop around the Fisher Body plant on a whim. When the need arose, a formal procedure had to be observed, approvals required. He did have knowledge of body fab processes at Fisher but probably spent relatively little time there.
Nice to look at pictures, but they don't capture the pace of manufacturing at the plants. Phil Borris, author of the excellent book "Echoes of Norwood" invited retired workers to MCACN a few years ago for a Q & A session. They had video of the plant from the '70s, looked to be a tough, physical place to work. At 57 units per hour, workers had just over 60 seconds to perform some assembly operations.