The Updater will not “re-apply” the firmware; only “update” it. If your device is already running the latest, the Updater will do nothing. But it is simple enough to use the manual installation instructions in the firmware post to re-apply your fimrware if necessary.
Actually, it’s better to do it manually than using the Updater. It’s just as fast, and the Updater won’t be phoning home everytime you plug into your computer looking for an update that will never come. Beside, it’s a resource hog and slows down your (computer) system.
