Billowhead (I'm going to assume you are using a Mac) If I use finder to look in "Macintosh HD:/Library/Audio/Plug-Ins" in the "Components" folder I have a file called "Mobius.component" with a file size of 51.1MB and in the "VST3" folder I have a file called "Mobius.vst3" with a file size of 52.5MB. (I think the plugins can also be under "Macintosh HD: /Users/<myusername>/Library/Audio/Plugin-Ins" and ableton will still find them but the above is how it's set up on my mac.)
Can you confirm you have the same?
Within Ableton if I select "Plugin-Ins from within the "Library" section of the left-hand browser window I see a list of plugin-in creators including "Circular Labs". Clicking on the small triangle to the left of that name expands the entry to show two Mobius entries (one for the Audio Unit and one for the VST3).