Production Number Data is about the best you can get in regard to trucks built before 1966. Here's that data http://reocities.com/MotorCity/speedway/7756/production1.htm

Here is some code data for the 1963's http://www.c10trucks.com/forums/showthread.php?t=797

In 1966 Chevrolet did start adding the Service Production Identification Data, aka "SPID", stickers in the glovebox that identifies what options the truck had from the factory. http://i645.photobucket.com/albums/...20Parts%20Identification_zpssmbgxfpr.jpg

Hope this helps thumbs_up
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John