Yes, they were all mixed up & at times, cars with VINs over 30,000 apart were actually very close on the lines. [/quote]

Wow, thinking about the required logistical management to have the right parts at the right time for that particular car must have been tough! Not to mention training of the employees on assembling different cars. [/quote]

This is why the Sequence number is easy to see at the top left of a broad cast sheet that drives the production of Vehicles, not the Vehicle Identification Number, VIN. Not sure why ROCK was put on any vehicle, an inspector would have a punch either that would put his assigned number punched into a broad cast or work sheet or and ink stamp punch. You see some of these ink inspection stamps on cars that have been stamped with OK in the engine compartment usually on or near the radiator cradle. Also there are other production sheets all over the plant that never make it into any vehicle telling the workers about what to sub assemble, the sequence number is the order on which the worker uses to build, not the VIN.