Getting a similar Shop Manual

Is it helpful knowing how they operated? Well if someone is looking for factory liturature, yes it is.
When I would go adealer to look up part numbers, I learned that the inital release of the '67 Parts Book did not have the Barracuda information. But one dealer had the supplement so I was able to look up the p/n for the 67 windshield gaskets and lockbrite as well as some other parts.

If I was to buy a Parts Book, or reprint now, I would know to look for or ask about the supplemental info that would have been inserted or added throiugh the year. If it wasn't there, I'd keep looking.
In contrast, if I was buying a 67 Shop Manual, I'm not going to look for the Barracuda or any other late info. It was never included in the book. It was always a seperate release like all the TSBs.