Kaplan Books: The retail ones, yes, they are that bad, as are most retail LSAT books.
Old Questions: Meh. They've evolved a bit, but I don't think they're useless.
So the books from Kaplan courses are OK?
I don't know. They're mostly just reprinted preptest questions, right?
I have no idea (I didn't attend the course, I got them at a used book store). They are not credited as reprinted official questions in the books themselves, but they could have been credited in the other material handed out in the course. They're marked "not for resale," so maybe standard citation rules don't apply.
I have no first-hand knowledge, but from what I understand, modern Kaplan courses use real questions but they did not always do so. I do not know the cut-off. How old are your books?
The "not for resale" books:
LSAT Home Study Book-2004,
LSAT Lesson Book-2005,
LSAT Lesson Book (unlike the previous book, in the table of of contents it says "Session 2 (Extreme 2), Section 3 (Extreme 4)..." so I think it might be from the Kaplan Extreme course-2006,
LSAT Stratosphere Workbook-2006,
LSAT Pacing Practice-2006 (Real LSAT questions cited within this book, and KLI just verified that they were real questions.)
The retail books: LSAT 180 2007-2008 edition