Wow, this thread is getting strange.
Back to the references on factory literature, factory brochures are not good reference material. The 1969 Firebird sales brochure shows the Firebird 350 H.O. with dual hood tach nacelles. The passenger side nacelle had a Ram Air hose connected to a modified air cleaner. This setup never saw production. Heck, there are also errors in the factory 1969 Pontiac Service Manual
. Some errors were corrected later via Pontiac bulletins, others were not. The most obvious error is a photo showing the different Pontiac V8 pistons, from the 428 to the RAIV. The captions under the photo are reversed.
GM had schedules to keep, profit margins to watch, employees to control, and they weren't thinking of future collectability. If something was wrong when the customer received their car (not a flaw, but a factory goof up), the dealer would correct it. What I've heard lately are more and more stories from the folks that were actually ON the assembly line, and they recall supplier problems, glitches in the machinery, even times when employees called in sick and someone filled in they weren't as careful as the regular employee, or vice-versa. If a supplier went on strike, or was late on their delivery, substitute parts were used. It happened all the time. The assembly line would not stop unless it was a serious problem with a major part.
That being said, we now have people 35 years later debating bolt head depth, washer design, the percentage of gloss in an A-arm, exhaust pipe hangers, etc. That's one of the problems I see with reproduction parts. Once a part is reproduced, everyone has the exact same part, and that's not necessarily correct. There WERE factory mistakes and goofs, and sometimes they used alternative parts for a day or two until the supplier was back in stock.
Some 69 Trans Am's had the stripes under the rear wing, some over the wing. Some were missing the front bumper arrowhead (supposed to be part of the Firebird 400 package), and some had hood scoop decals. Pre-production publicity photos show the 69 Trans Am without a front spoiler. Go figure....