I'm not exactly sure.!! I ordered from sweetwater last year. Here are some pics.
Unless you're running it on a UAD interface, it's Native.
I would download and run the latest installer (https://www.eventideaudio.com/support/product/8511/installers), and then restart your computer. There is an issue on High Sierra with plug-ins not immediately loading in GarageBand until a restart of the computer, which I suspect this is.