First in and first out would apply to most everything that was assembly line installed but the A12 cars were not completely assembly line finished from what I was told by Dick Maxwell who's personal project the A12's were. Dick said that it was no problem for Fleet Engineering and Product Planning to find openings or missing spots (due to many reasons) in the normal assembly line with the timeline "window" of first March 29, 1969 and then because of demand for more than 500 each A12 RR's and SB's another "window" of April 26m 1969. Sticking a 440 without the 3X2 carburetors into a '69 B-body was not a problem on the normal assembly line and neither was a 4.10 Dana or a 26" radiator or 11" brakes. The biggest issue was the carburetors, fiberglass lift off hood, the hood pins and brackets and a couple of smaller items like the high idle solenoid and plastic clip on the valve cover for the wire, and idle adjustment for that system, putting the special idle adjustment label in place and installing the A12 air filter tray and cover etc., The remaining A12 Lift-Off-Hood, carbs etc., where done in a special area at the end of the normal assembly line according to Dick Maxwell where those components were stored and pretty sure those items were not in a first in, first out normal production line format of storage. I would think that if the LOH had a production date those dates would also be all over the place along with anything else that was not possible to install on the assembly line with a GTX, Satellite, Cornett, R/T etc., There is also the story of finished production delays due to a delay or shortage of Edelbrock aluminum intakes from them along with some quality issues too that may have caused the dates to be somewhat out of sequence.

MikeR