The Certicard was used for vehicle warranty administration. When the vehicle repair order was written, the Certicard could be run through an imprint printer (think credit card machine from back then, which used carbon-type paper to leave the imprint of the items on the card, printed with a Dymo label maker sort of machine) so that the VIN was recorded correctly and the owner's name was there, too. No more, no less. Chrysler placed them in the dedicated pocket on the back of the core support by the battery. GM did their's on a particular rear page of the owner's manual. Chrysler had the better idea in this case.
IF you found the VIN decode in the Factory Service Manual, there might be some additional information in the 1966 Chrysler Parts Book (free download at
www.mymopar.com). Much of the Data Plate decodes can be in the front pages of the parts book, too. For factory sales and trim order guides, with the sales Order Guide providing option code decodes and similar things related to the vehicle,
www.hamtramck-historical.com is the place to go to find these things in the "Library" section.
In the Dealer Order Guide, there are also many specs for the vehicle listed, too.
Enjoy the discovery! And welcome!
CBODY67