MP Extensions Manager (1.36 x64) not displaying all installed extensions (8 Viewers)

[2BitSculptor]

Curious. Shouldn't the Extensions Manager be able to list all the previously installed extensions and plugins in the Plugins folder? Specifically, MP-TV Series and MovingPictures (and a couple others) are operational in MP 1.36 x64, installed in earlier versions, but do not appear in the Installed Extensions Tab in the Manager; they are still listed in the Known Extensions Tab. Would it be safe to install/update them from Known Extensions even if they are already installed?