That is still the GM Information Center number and I think it is unlikely that they still do this what five years later, but try if you like.
In all likelyhood they will just refer you to the Heritage Center. There you can download the data book specs. that were included in the package but not the fluff.
http://www.gmheritagecenter.com/gm-h...tion-kits.html
Just select for the drop down for our earlier vehicles.
"Chevrolet Trucks (All Models Not Listed Below) Show"
It is not complete however and this link has been posted here on 67-72 before several times I know of.