None of the writers has ever mentioned there being "exclusive" lore in the RPG. It will be current through the first 10 books, the published short stories, the "Welcome To The Jungle" comic, and the upcoming novella "Backup". The info based on that source material will apparently be quite detailed.
I know that updates are planned. I think Fred said they might be PDFs. Further down the line, we may get a second edition. Remember, however, that there are 13 books left to go. And right now they're concentrating on getting the game out in the first place.
NOTE: I am in no way involved with the game or with Evil Hat. I'm just repeating what I've gleaned from this site and the podcasts.
I
am involved with the game and Evil Hat, and I can say that you're more or less correct.
* There is no RPG exclusive lore. It's all sourced from the books (with maybe one or two bits expanded upon in email exchanges with Jim).
* It will be current through the first 10 books (ending with
Small Favor), the published short stories ("Something Borrowed," "Heorot," and "It's My Birthday, Too"), and the "Welcome To The Jungle" comic.
* As for "Backup", it's a little problematic -- given the narrator, it doesn't fit our take on the way the game presents itself (Billy and the Alphas trying to make this game to duplicate the effect
Dracula had in the Dresdenverse). However, nothing in the RPG will contradict "Backup."
* "Backup" might be a candidate for a PDF supplement... but that's more Fred's call than mine.