All of the engravings appearing in "The Nine Gates" were commissioned for the novel (and not the movie) by author Arturo Pérez-Reverte himself. The only exception is the one showing The Girl riding a dragon, which was altered to make it similar to the actress' face.
The Don Quixote that Corso buys at the beginning of the film is the very famous Joaquin Ibarra edition, published in 1780, which is generally considered as the best, and most beautiful one. He also mentions the Hypnerotomachia Poliphili (Venice, 1499) printed by Francesco Colonna, dubbed "the most beautiful book ever printed". These amazing illustrations can be viewed on the internet.
The bag that Dean Corso carries throughout the film is a small bag carried by French soldiers around 1935. It was used to carry ammunition and other small items. It is called a Musette MLE 35.