Body Unit Number
Short answer: The Fisher Body Unit Number on the firewall trim tag is an internal sequencing number, unique to each assembly plant — it is not sequential and has no direct relationship to the VIN or build date. The Broadcast Department assigned it based on the order’s color, model, options, etc., and cars weren’t built in the order received.
- Two cars ordered the same day can get very different unit numbers — e.g., VIN 164250 / Body Unit 4886 vs. VIN 164279 / Body Unit 7679.
- The trim-tag build date marks the month/week the body began in the body shop (Body in White). It generally took under a week from receiving the trim tag to leaving Final Assembly, and only about a day to finish a car once it moved from Fisher Body to the Final Assembly plant.
- The Billing History invoice date is when the car was “bought off” after Final Assembly (starting billing/delivery). Special orders can show a few weeks between the body build date and the invoice date.
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Content last modified: June 13, 2026 at 10:06 am
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