Pretty much. But you could also re-target your mesh to get the same animation you produce or correct with the plugin to work with your cusom mesh.
It becomes especially easy if you make a custom character to rig it however you prefer and add as many bones as you really need and then just re-target it to the motion you already authored or got off the marketplace.
all you need to do is match the initial A pose general position or switch both to a t pose to get near perfect results.