In the early stages of the Cultural Revolution, Mao Zedong reviewed the Red Guards seven times on Tian'anmen Square. The first one, the "Mass Rally Celebrating the Great Proletarian Cultural Revolution", took place on 18 August 1966 (with some one million Red Guards present), the last one(s) on 25-26 November 1966 (2,500,000 Red Guards). Photographs taken at the time show that during the fifth rally of 18 October, and the eighth rally of 26 November, Mao was driven through the crowds in a jeep.
Moreover, note that for unknown reasons, this poster was published in November 1976, whereas all the other ones in this series already were made available in August of that year.