i always thought that customer orders got priority on the builds, and also that high volume dealers got preferential treatment..
All that plus material availability, paint color, shipping arrangements, etc.
COPOs have provided some insight as to how orders could be "pulled in" or "pushed out." The initial 50 unit ZL1 order was confirmed on or about Dec 6, 1968. Cars #1 & #2 were final-assembled Dec 30 and delivered to Gibb Dec 31, 1968. That's 14 production days after they were ordered-the Body and Chassis Broadcast copies have this note: "SHIP 1230 ESTES REQUEST RED HOT." Pete Estes was Chevrolet General Manager at the time. The BDY numbers for those cars are 222002 & 222003; much higher than other Camaros built at that time. It's just my guess that they were waiting for ducted hood parts to arrive at the plant as these were likely the first ZL2 cars built at Norwood. Build docs for both exist; they had pilot ZL1 engines built at Flint [not Tonawanda] weeks prior as were the BE axles. The next Gibb ZL1 was completed about March 4, 1969. It has a BE axle dated Feb 25. Axles were built in Detroit so those cars were released to production the instant the axles arrived at Norwood. Central Office employees have stated that BE axle availablity dictated COPO scheduling.
BTW the earliest Gibb ZL1 BDY number 222001 was built 43 days after 222002. 12 other Gibb ZL1s with higher numbers were built prior to it. 222001 was the first Le Mans blue ZL1 so that may have been a factor.
There was a Central Office memo sent to dealers early November 1968 advising that additional Z/28 orders would not be accepted until engine production could catch up to existing orders.
There are too many variables involved to draw any conclusions from a BDY number relative to a VIN.