https://gemini.google.com/share/c9af8de05628
I did manage to get one image of a piano keyboard where the black keys were correct, but not consistently.
https://imgur.com/ogPnHcO
Even generating a standard piano with 7 full octaves that are consistent is pretty hard. If you ask it to invert the colors of the naturals and sharps/flats you'll completely break them.
https://gemini.google.com/share/c9af8de05628
I did manage to get one image of a piano keyboard where the black keys were correct, but not consistently.