Wondering if the “Recording piano” needs it’s own instrument.
This was the name for a piano that was fitted with a carbon rod on the underside of each key, and under each foot pedal, that dipped into mercury, allowing the recording of the changes in electrical properties that resulted from playing the piano to be made. (Doubtless the modern versions avoid mercury.) The recording was some form of pianola roll.
The keys are being pushed, strings are being struck. It’s just a piano. (We don’t have “piano microphoned by Sennheiser” as a instrument separate from “piano”. The electrical circuits are irrelevant)
What was being recorded was the electrical properties of circuits intrinsic to the recording piano. It was the changing pattern of these electrical properties that was the reason for the performance. (That it made sound simultaneously is irrelevant as the sound was just an aid to the player. Not what was recorded.)