I learned in 2007, and was reminded in 2013, that nothing teaches you about playing Runescape like playing Runescape.
Tracey West's book was useful, but discovering things for myself was magical and fun. I soon stopped turning pages in favor of clicking my mouse. I enjoyed just nipping through gates and meandering down lanes, solely to find out what was there.
That said, the game moved on a lot in over half a decade. It took us with it. As players, we have forgotten so much, which was second nature in 2007. This handbook is like a moment frozen in history. It tells us in plain text all that we once all knew.
However, its scope is quite limited. It covers only the F2P lands and doesn't so much as peep through the gates of Taverley.
If you're buying it as a genuine guide to Old School Runescape 2007, as released in 2013, then I wouldn't bother. It might give you a momentary step up as a revision - perhaps a few days before your friends remember - but you'd just as easily rediscover it all by playing the game.
If you're considering it as a geeky gift for an old time Runescape player, then yes, it's fun and nostalgic. I'm keeping my copy accordingly!