99.5% of the NOS parts in those books are gone, from GM and on eBay... you might be able to find an Oldsmobile nameplate or some common cross platform mechanical and engine items like an AIR tube, fasteners, hinge or handle but that's it.
Cosmetic stuff like trim, lenses, body panels, decals and interior items are pretty much gone... you're going to have to put want ads up for that stuff and most of the hoarders aren't even selling them.
I've searched the internet about an hour a day for the last 15 years with a list of 2000 numbers, very rarely does anything comes up.
I might have some spare stuff if you're looking for anything in particular.