GNX 50 is in the southwest suburbs of Chicago. I have spoken to the owner before. I haven't seen him for awhile. I will try to get in touch with him and pass your information along.
Mike R.
87 GN hardtop.
87 Olds 442.
91 Cadillac Brougham.
06 Pontiac Grand Prix GXP.
If you can't find him, I'd like to have the book. My car did not have the book when I bought it, so even if it's for another car I'd like to acquire one.
Once in a while unnumbered books show up on eBay. I got mine for $55 shipped in the original cardboard mailer, and I have a friend that got 5 of them for about the same price. If you look around some you can find them.