I think there are some inconsistencies in the naming of Chopin's pieces. The title I listed is on 2 of the 3 version I have (3rd is untitled).
Edit: I just looked on
Amazon for the album I referred to earlier. In the tracklist they don't have any number for the track, just " Nocturne In C Sharp Minor, Op. Posth.".
Also I was wrong about it being on 2 of the version I have. It is only on 1.