It means you have Serial Numbers in the registry for those sceneries as well.
It doesn't matter if you have installed the scenery or not, what matters is that you have serial numbers inserted, maybe coming from a previous installations, and this make sense, and it's designed to work this way because, when you remove the scenery, serial numbers will not be removed, so you'll not lose your activation even if you uninstall the scenery and even if you remove Flight sim entirely.
Of course, if those serial numbers are correct, they'll activate, so you'll find the scenery active and registered already the next time you decide to install it.