Anything that says Installed is clear. Some applications say Install, but they are greyed and touching the button has no effect. Those have, in many cases, been superseded. If a button says Download, there is an update available for download/install.
If you have Mountain Lion 10.8.3 as your profile indicates, there are updates. There is an update to 10.8.5, a Supplemental update, and a security patch from February/March. Click Updates and see if you are shown ML updates.
If you have not updated your profile, what Mac OS X version and build do you have? You find that by - apple left side of the menu bar, About This Mac and under the Apple logo is the Mac OS X Verizon number, click that and you see the build number...a number, letter, number.