From build week 12B — the second week of December 1968 — the Norwood plant stamped an Xnn code on 1969 cowl tags. It was an internal aid telling Fisher Body which trim and paint treatment a body needed, but because the codes track drivetrain and trim families, they are now one of the most useful checks on what a 1969 car originally was.
- X11
- Not a big block and not a Z/28, with Z21 style trim
- X22
- Big block, with style trim
- X33
- Z/28, with style trim
- X44
- Not a big block and not a Z/28, without style trim
- X55
- SS350, without style trim
- X66
- Big block, without style trim
- X77
- Z/28, without style trim
- Z10
- Indy Pace Car replica (hardtop, RPO Z10)
- Z11
- Indy Pace Car replica (convertible, RPO Z11)
X-codes were applied at Norwood, Ohio only. A Van Nuys car never had one, so its absence on an LA car proves nothing. Norwood began stamping them with build week 12B — the second week of December 1968. Earlier 1969 Norwood cars predate the practice and will not carry one. The codes told Fisher Body which trim and paint treatment a body needed. They map to drivetrain and trim families, which is what makes them useful now — but they were never intended as a record of what the car was. A separate D80 stamp (spoilers) sometimes appears but was not applied consistently.