The body number on the cowl tag was assigned when the plant accepted a dealer order for production; the dealer order number (which was pre-printed on the dealer's order blanks) didn't serve any direct purpose on the line in production, although it followed the car on all the Chevrolet paperwork (Broadcast Copy, window sticker, Car Shipper, etc.). The body number on the cowl tag showed up as the "Ident Number" in the top row on the Broadcast Copy, and also showed up in the upper right corner of the window sticker and Car Shipper. In the scheduling computer, that number tied the unit back to the specs on the Dealer Order.
When each body was scheduled out of the Chevrolet Body Bank to the beginning of the Chevrolet assembly system, it was assigned a "sequence number", which appears at the upper left corner of the Broadcast Copy - that's the exact sequence in which the car passed through the Chevrolet assembly system, and that was the important number as far as the plant was concerned while the unit was in the system; once the car came off the line, it was meaningless.