Keith,
Sounds to me like the piano at one time had a player mechanism. If
there are no other indications undr the piano for a player installation, then
you may have had a push-up player,made by Hupfeld, Apollo, Angelus, Aeolian, etc.
If there is evidence under the piano of a player having been built-in, then these plates
may have held the slide out drawer.
It they are all at one end, then it may have held a Hammond Solovox.
Ed Hilbert
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