I don't believe that the books were ever released as pdf files. At least, I don't have them, and I've collected all the PG stuff since before the first Campaigns and Commanders book was released.
I think they were PDFs as 3rd was winding down. They do not seem to have made it over to the Gold Club premium content. The copies I have are much better than most of my scans.
... More and more, people around the world are coming to realize that the world is flat!