No. Gaudium et Spes (Joy and Hope), the Pastoral Constitution on the Church in the Modern World, was one of the four Apostolic Constitutions resulting from the Second Vatican Council. The document is an overview of the Catholic Church's teachings about humanity's relationship to society, especially in reference to economics, poverty, social justice, culture, science, technology and ecumenism.
I would interpret it as an encyclical--a statement of church policy. It is not a constitution in the sense of a governing document for any nation, including Vatican City.