I also have wondered if they are all the same. Why do some manuals on Ebay say that some pages may be blank or so light that they are hard to read? Other manuals for sale don’t say that. Are there differences in the quality of the print?
The sellers on Ebay that tell you about the balnk pages, etc. are just being honest. That's how the printer describes what they get from trying to copy original GM manuals. The arguement for the "bad pages" is you might find something you can use on them.
As for the other sellers... Hey, it's Ebay... Buyer Beware!
What I'd like to know is: Does anyone from CRG have a copy of an original GM manual? --Or at least seen one in the last few years? What do the originals look like now?
There are still original (expensive) P&As floating around, which are in pretty good shape. But I presume there were more of them printed and they got out into the automotive world...