The below info are things I have written in response to similar questions over the years and saved. It is not a direct answer to ALL of your questions but you can read through it and find answers to most of your questions.
Y9 cars were code so for a varity of reasons, and not often orders written by dealers but rather the factory.
Without the IBM card, original invoice, window sticker, or the Certicard, there is no way to determine the original receiving dealer.
999 paint code could be ANY color available from paint manufacturers regardless of auto maker or THEIR color name. As others said, you will have to find a hidden area with original pain in tact.
The new model year cars began being built around August 1. This date varied from year to year and plant to plant for various reason with regard to how big of a job it was to re-tool for the new year or if a particular plant was making a complete change over as to the models they were going to built for the up coming year. Sometimes the change over did not meet schedule and some times they were ahead of schedule, but the target date for start up production was August 1, but even when ahead of schedule they did not start early as the work force was not scheduled back until August 1.
The production began in August for promo, advertising and show cars for the dealer new car shows at the regional or zone level. These shows were held the first part of August. At the time of the showing the dealers sat down at the show with their sales rep and they made their initial sales order for the cars that were to be in their dealership for the new model release to the public on October 1. At this time the dealer received their new car order forms for additional orders, Dealer Data Book, the Color and Upholstery Book, however they did NOT get their brochures at that time but were rather mailed to the dealers shortly before October 1.
Back in the late 60s and early 70s cars typically took 4 week from the time the dealer mailed the order until the time the car rolled off of the transport at the dealership. So, some dealers got their new models earlier than others depending on how the orders were input into the system. When you got your new models you covered or hide them from the public and were not allowed to sell them until October 1.
The (SO) sales order, NOT shipping order on the fender tag, and it's number were the first document in the life of a car. After it was written it was determined by the corporate office as to which plant it would be produced at depending on which plant built that particular model and was geographically closest to where the car was to be shipped to IF it was predestine for a dealership. At that point the sales order info ( AND the V.I.N. which was assigned at this point ) were input on the IMB computer that generated the IBM card and from that point the plant that was to produce the car picked up this information from the IBM system. The ONLY number that was generated by the actual production plant that produced a given car was the SEQUENCE number that is the first set of characters on line one of the broadcast sheet. This number should not be confused with the sequence portion of the V.I.N. and they had no corrolation to anything other than the producing plant at the TIME of the cars production. This number is simply the ACTUAL sequence that the car went down the assembly line.
In the case of the A12 cars since they were sales bank cars the sales orders were written in house at the corporate office and they were not destine for a particular dealer.
The order # comes from the order forms that were sequencial but since they were distributed throughout the country to different dealers and were also available to the personell that wrote the orders for the sales bank cars they were all mixed up and seperated before they were input on the IMB card. I would think that with the amount of orders that had to be filled out at the corporate office for the A12 cars and other sales bank cars that there was more than one person filling them out over a course of several days. When you factor in people working at different speeds, lunch and coffee breaks, how many one person might hold compared to another person before giving them to a key punch operator, etc., etc. these numbers could be all over the place.
Now, you have to understand that the cars that were ordered on the original sales orders that were written for these A12 cars were delayed due to the intake manifold shortages. ALL of these cars were SUPPOSED to be built by the time that the cars were announced to the buying public, and ALL were to be built in the four special colors. AFTER the initial sales bank cars were basically sold the factory was going to accept orders in any available color and any available options.
It is my personal believe (although I have no factory documents to confirm this) that the V.I.N.s for the UNBUILT cars waiting for manifolds to become available, were re-assigned for some reason. Probably because they were concerned that they MAY run out of model year build time before the manifolds became available and there would be a hole in the V.I.N. number sequence for cars that WERE built. This also explains the cars built in colors OTHER than the initial four, that all of these cars were SUPPOSED to be built in. Customers that had been waiting to "special order" an A12 got EXISTING orders customized that that had not yet been built converted to THEIR orders, although they were still classified as SALES BANK cars.
What all of this boils down to is that there MAY be some corrolation of V.I.N./SPD/VONs for the EARLY built cars from the master order list to other cars being built at that same time, BUT, the numbers for the other A12 cars are all over the place due to the manifold delays.
