So your account is marked as having it "purchased" then?
I may have been wrong on this one. Can anyone confirm?
I think you get the version you got when you received your Mac, but you aren't counted as 'purchased' for future versions.
Since we haven't seen true future versions since the Mac App Store released, I don't yet know how they'll handle that. They may make an iLife 2013 or whatever that is separate from the current, or they may continue the trend of just small continuous updates.