You guys are getting away from the real purpose of this thing. It's in the days before computers but we had teletype (since before WWII). That made it easy for the Scheduling Dept., in each plant to print a list to each department, showing the 4-digit in-plant rotation number and the necessary options pertinent to that car in that department. You could look down the line and clearly see the four-digit number hand written on each car, so everyone knows what's coming.
But some parts need time to be assembled off-line in a sub-assembly operation. When that part comes to the main assembly line, it better be for the right car because this line doesn't stop.
For instance, why would Paint care what axle or engine is going in the body? They need to know what color the car is. The Instrument Panel sub-assembly needs to know if the car has a radio and which one (Town & Country or basic), etc.
Trim wants to know what electrical accessories so they can install the correct cable assembly, steering column color, carpeting color, door and cowl panels, headliner and windlace color, convertible or not (because they build the backlite with a weatherstrip), etc. Chassis needs to know which engine/trans, which exhaust system, axle ratio, etc. Final needs to know if the car has A/C, which tires, battery, seats in what color, vinyl or leather, etc.
Each little 'thing' and all this has to come together on the assembly line and THAT is why you see build schedules. Rather than throwing each one away, the Final Seat Sub-assembly worker might stuff his in a seat bottom. It may only show a select few items about that car for his dept. As I said, each department came to work with a fresh set of printed sheets, usually in a book form for the Foreman and his Utility Assemblers.
So, what happens when the Quality Control Dept., randomly picks a car out of the line to destroy it in a salt test or spot weld teardown? That's when Scheduling goes to work again, constantly updating the broadcast sheets, trying to avoid a mad scramble involving many hundreds of workers.
I chuckle when I hear that someone wants to duplicate a build sheet. The truth is none of them showed all the options. You would have to go around to each dept., and get the one for one particular car. The window sticker didn't tell everything either. It might show the color, engine, option packages, etc. It did not show axle ratios or the fine details that are in that car.
I guess one needs to be employed in an assembly line operation in order to understand the big picture. It is complicated. - Dave