Careful observation of the marks on the wainscoting reveal all the sets were constructed from the same flats.
One of the 50 films in the 4-disk boxed DVD set called "Treasures from American Film Archives (2000)", compiled by the National Film Preservation Foundation from 18 American film archives. This film was preserved by the Museum of Modern Art. This version has a piano music score and runs 17 minutes.
The text of the first telegram is signed 'GWB', the initials of camera George William 'Billy' Bitzer.