You and a lot of Chrysler fanatical Sheep really don't understand the Big Picture responsibilities a major corporation has to it's Regulators and the Government, do you?
The importance of regulators was not terribly high in the 1960s, and over time it has become even less important for cars that were built 50+ years ago.
On the other hand, considering Chrysler's brush with bankruptcy, its buyout of AMC, and its own buyout by several European companies, it would make sense that old production records were tossed.
I believe some nitty gritty are in the hands of collectors, and they are the best chance for enthusiasts to learn more about their cars. I don't think they'll be invoices or anything like that, but if they were sold in Canada there's probably a better chance something exists as I believe there's a law regarding maintaining records of production vehicles. This is the reason why GM of Canada has good records.
As such, your comparison with GM is not great because it involves contemporary production vehicles from a time when regulators had much more influence in the industry.
So, no, not end of discussion--talking about it is the first step in getting closer to an answer.
