I am sure you can google same. If it was protocol..you can bet Reagan followed protocol. Reagan would never ever insult a world leader in their counntry. Never. (Remember when W had to wear that silly outfit and dance??) It was painful..but he did it.
No. You prove your nonsense.
Part of US culture, since the founding fathers, is that a POTUS never ever bows to a foreign leader. NEVER. This was in response to the American value that all men are created equal especially in the face of Royalty.