they were amongst the installed game files as OGGs (in the GOG version at least). Pretty sure GOG would have included the soundtrack as bonus content if they could have gotten the rights.
So, if they're in the game folder as you and aluinie have written, but not in a download file from GOG's website, does that mean they haven't gotten the rights? What does that mean for purchasers of the game on GOG? Do we have rights to copy the music folder?