I updated via the LiveUpdate and although I seem to have the correct version in P3D (with the new fuel truck) Windows is still showing v2.50.11 installed.
Windows Control Panel won't show the version of the installed files, especially when they are updated with the Live Updater. It will only show the version of the installer you used to *originally* install a product, which basically mean which Uninstaller will be used.
So no, it's not a problem. If the Live Update completed, you ARE updated.