There were a couple additional packages (dependencies) that were required when I installed the deb package. I doubt the .so plugin extracted from the deb package will work without those. If you want to extract the plugin from the deb, look at
this info to figure out what dependencies it requires and check if you have them on your system. (Other than the VST2 SDK, which you won't require since you're not building the plugin.)
I'd originally tried to run the .so from the deb and reaper wouldn't recognize it. So it'll probably happen to you too if you don't have the dependencies.