A factory assembly manual did exist for each car and year. It was full of engineer drawings for how things went together on the assembly line. Chrysler kept them afterwards.

Copies of numerous pages have escaped and been copied again multiple times and shared on the internet occasionally. Year One used to sell packets of copies of them, separated by subject matter. I purchased copies of the E body stuff they offered, but when it arrived, most of the info was B body engine stuff. They can be hard to read, not the greatest copies. I think Barry had several of them available on his website for a while, but Chrysler sent him a cease and desist letter. At the time, Chrysler was cracking down on that sort of thing because they still had the originals and were working towards making nice clean complete copies available through Faxxon Auto Literature. It was very exciting, and I was eager to get my hands on the E body books as soon as they became available. Faxxon started with the earlier years and planned to release later years in chronological order as soon as they were ready. They came out with a few for mid 60's mopars that I wasn't particularly interested in, but then the economy crashed and Chrysler was eventually sold to Fiat. I'm pretty sure the project with Faxxon was cancelled.
We were so close!

I just looked at the Faxxon website, and it's all different now, so I can't find the few they had, if they're still available. I think it was a few cars from the 64-67 time frame, I'm not sure.

Tav