I'm not quite sure how to follow the second step of directions. Could you elaborate further, please?
IIRC, the music is actually in the correct directory now, so you don't need to copy the files.
You just need to edit fallout2.cfg as shown after the OR
When you edit it, there should be two lines, as shown in Weclock's post.
What you need to do is edit them as such:
Also, IIRC, you need to actually run Fallout 2 once for the fallout2.cfg to be generated.
For some reason I'm not sure of, whenever the game installs, the music_paths' directories are nothing but gibberish instead of being the correct directory (or, at least, that's the way it is for me). Oddly enough, when I installed the games under Wine on my Linux machine, the paths were correct.
EDIT: There is a distinct possibility that this may just be an issue with my install, as well. If you have a ./sound/music folder in your install directory and your fallout2.cfg file reflects that, then nothing needs to be done. Mind you, my latest install of the game was using the newer installer from GOG just a few days ago, so if you have the older one, you may need to copy the music files and/or edit the fallout2.cfg.