You don't have many Addon Manager installed: the Addon Manager is always one, since the files are the same, and in the same folder.
What you have, instead, are multiple Uninstallers for it, which is not normal, but it won't create any problems, just that Windows have several copies of the uninstaller.
If you want to "clean" your Windows Control Panel, you can remove them all, and reinstall GSX using its full installer. There's no need to a separate Addon Manager installation, if you install a product (GSX) or a scenery using its *latest* installer, because all the installers comes with the latest version of the Addon Manager.
The only reason so install the Addon Manager separately, is to update it without downloading a product full installer again, or to install a GSX major update without downloading the whole GSX installer again.
But in your case, if you want to get rid of the multiple uninstaller, you'll have to remove all the Addon Manager copies, DOWNLOAD the full GSX installer that is online now and install it. There's no need to install the Addon Manager again, unless its gets further updated in the future, and GSX tell you to do so.