I am working on an early, 1915 Weber Duo-Art upright.  The serial number
is on a celluloid plate at the top inside of the bass side of the case.
If I lift the lid and look left, it is right there.  The plate has the
serial number and underneath are the words Duo-Art and Pianola.

As to the tubing chart, John Sampson was kind enough to send me one for
the years 1913 through 1918.  I am forwarding it to you by direct email.

Joseph Osborne - Antique Keyboard Instrument Restoration
Carlisle, Pennsylvania, USA