Was the guide a GW one or one that someone did? In the Two Towers Journey book they have a paint guide as well as in The Return of the King Journey book. (Both are similiar, the Two Towers one has how to do the skin in addition.)
The best one I found was in White Dwarf (don't know the number, I just ripped out pages I liked) in the article Winged Nazgul.
All the articles use the old paint.
Edit: Thanks to The Last Alliance index of White Dwarf articles
http://www.thelastalliance.com/viewtopic.php?f=3&t=8189 it was in White Dwarf 362, February 2010