How do I update Pages to 4.2 on Mountain Lion?

I saw the update on Lion but decided to wait until I updated to Mountain Lion. But upon looking I found it led me to the app store with no update for pages '09 from 4.1 to 4.2. I have looked to the pages app but it only has the buy icon. I am not buying a product I already own, so where is the update for it? Does this mean I'll have to unistall Mountain Lion/reinstall Lion then update then reinstall Mountain Lion again? ARGH!