Legacy input and SteamVR bindings

To get proper support for Knuckles without upgrading to SteamVR 2.x (which is to big a hassle with a released game built upon SteamVR 1.x) I want to include some default bindings with our game. Is it possible to distribute the .json-file that can be exported from Controller Settings and allow a Unity game to use them by default instead of the "Index Controller Legacy Default"? I have tried both bindings_knuckles.json and steam.app.<appid>_knuckles.json in the application directory, but neither seem to be picked up.