I must have missed the request for information on Seeburg coin pianos.
Presently I have two: (1) Seeburg KT, with flute, # 79062, and
(2) Seeburg A # 31655.

The information I have indicates the KT piano was build by Haddorf in
1918, before Seeburg started building their own piano backs about 1923,
and started re-numbering at 150,000 to avoid confusion with the vender
pianos.

The rubber stamp number on the plate is valid as far as I know.  The
number was also stamped on the underside of the hammers if they are the
originals.

Jon Guy