The Emperor’s guards are called “Royal Guards” and Luke calls the Emperor “your highness”, but we already knew in 1983 that he’s a politician who got the legislative body to vote absolute power to him, not someone who inherited a throne.
Another thing the PT got wrong.
As I said, it was already known in 1983 that Palpatine was elected to be the Republic’s head of state. In this case, the prequels were just showing what was already known.