The ASIN for the version of Pride and Prejudice (tied with the Free one from Audible) was not in my Amazon account or in Calibre, but I was able to find it directly in My Kindle Content folder.
Here's the ASIN: B000JMLFLW
-Hope this helps you to get it!
Glad you were able to get it too, I hoped I wasn't the only one!
- Make sure you're signed into your Amazon linked Audible account before trying to get it (as sufue also said).