That type of thing was pretty common in spy novels. No idea how common it was in practice.
Depends on the author.
Some authors are well-known for the thoroughness of their research. Some spy novels have been so accurate that ex-intelligence people have approached the authors to ask them how they knew certain things, and to offer them more information that would be useful for new manuscripts.
Can you give some examples of authors? I'm not a huge fan of fiction anymore really, but I think I'd enjoy a book that's decently "accurate" like that.
