If renamed just Hilton in 1971, they must have changed the logo about then.

The Iranian Revolution was in 1979, which I guess is where Rich's logo began., so it came after the old HILTON INTERNATIONAL one -- Wikipedia:
"The Iranian Revolution (Persian: انقلاب ایران‎, romanized: Enqelābe Irān;), also known as the Islamic Revolution or the 1979 Revolution,[4] was a series of events that involved the overthrow of the last monarch of Iran, Mohammad Reza Shah Pahlavi,[5] and the replacement of his government with an Islamic republic under the Grand Ayatollah Ruhollah Khomeini, a leader of one of the factions in the revolt.[6] The movement against the United States-backed monarchy was supported by various leftist and Islamist organizations[7] and student movements."

Wikipedia:
https://en.wikipedia.org/wiki/List_of_flags_used_by_Iranian_peoples

Sorry to "beat this to death," fun looking it up. I must have better things to do, but more work.

Robt.