Beethoven's compositions are in the public domain because he died before Mickey Mouse first appeared on screen, but specific copies of his works may still be covered by the editor's copyright.

For the benefit of non-musicians: Editors, especially of older works, routinely correct mistakes (and sometimes disagree about whether the composer made a mistake!) and depending on how verbose the composer was may add their own indications of speed and volume; in some cases you get instrument-specific annotations as well, e.g. fingerings and bowings in violin parts. The Bach solo violin partitas are immediately recognizable as the Bach solo violin partitas no matter who edited them, but if you're familiar with the editions you can definitely tell which one a violinist learned!

Yes, like a novel, but the sound of a note isn't.