I definitely saw "fake" books regularly when I lived in SEA. Especially in Vietnam, street sellers catering to backpackers. They've often been wonky copies, out of low-grade paper with often blurry covers. Easy to spot the difference to a genuine edition.
But I've never seen this in europe, online or offline. I guess police and costumes are much more strict about copyright and fake products in general. Can't speak for the US or other places, thought.
I'm glad that I saw the movie before reading the books. I could ravel in the fact, how good they are, especially compared to the movie, instead of getting frustrated and angry.