Craig, there is a fairly early (1916) Steinway upright Duo-Art on eBay
right now, item 130270049257, and the pictures are very good.  It would
be interesting to compare this instrument to what you have.

It seems that by 1916 the preference for an electric reproducing action
exceeded all expectations, and some pianos intended to be Metrostyle
Themodist foot-pumpers received the electric-only Duo-Art instead.
This is one such piano, never modified to eliminate the pedal door.
The only non-original components I see are the electric motor and the
spoolbox strike plate.

Early upright Duo-Art actions were built with brass strike and patent
plates, with wording on the patent plate beginning, "THIS PIANOLA
ACTION".  Later production was of aluminum with wording beginning,
"THIS AEOLIAN ACTION".

I once owned a 1914 Steinway upright Duo-Art on which the entire
spoolbox had been changed to the 'twenties type with open top and
electric light, improved automatic tracking, repeat on/off switch,
wooden take-up spool with air channel and port, and tracker bar
fashioned from sheet instead of solid brass.  If your spoolbox is
original, it should have the two extra tracker bar ports once used for
automatic tracking.  Perhaps your 1911 piano had some sort of serious
problem in need of correcting before player installation, and was held
back for that reason.  Or maybe Duo-Art production, at least on the
experimental level, began earlier than I had thought.

The "tall" roll drive motor is another characteristic of the early
upright actions.  Later on, no doubt for economy in production, the
same motor was used in both uprights and grands, but with screw holes
for mounting brackets drilled in different positions.

Jeffrey R. Wood