The IP line would be set up for the build of the dashes and all the components and would be a sub assembly line with high senority. Likely you would work off the broadcast sheet for assembly and that is why the sheet would be on the back of the glove box.

Hemi Torque Boxes being put on some E Bodies that do not take them and some that should have them and don't is easy to understand if you have ever worked in an Automotive Plant. The Body shop is for newbies and low seniority so just keeping up with the extra parts going on like Torque Boxes and understanding the Build Sheet when you have just started would be common. Usually three days of training or less and you have to use two or more spot welders on every vehicle or chassie. Now you relying on an inspector that is ticked at you screwing up and is sick of doing your job and lets things go and just does not want to do his job of inspection or a repairman that is tired of a new employee every week or so and keeps the line running and sends it to reject for a fix that they would not do because it is just to hard to do it and would ship it with or without boxes.