It's an interesting thought. I think keyboards originated in Ancient Greece, and I also think Ancient Greek is read left to right, so it is plausible that's why piano keys go left to right in terms of ascending pitch. I think a more interesting question might be how many keys [per octave] there would be on a keyboard instrument if it had been invented in an Arab country, because as far as I can tell, they don't use the 12-tone system used in most Western music.