I have been using this mod for a while, and was unaware that it actually added a couple of new discs, until I discovered them in the Creative menu.
This was on a singleplayer world, so there was no real issue, but when I went to use this mod in a vanilla server, the discs were still obtainable through the creative invetory, causing a ghost item to appear, and available through autocomplete of commands, but would give an error when requested (because the server doesn't know about the item).
My request is to have a setting in a config, that allows you to disable server side functionality, for full client-only compatibility :)