According the the Archives of Vacheron Constantin, the present watch was manufactured in 1958
Affectionately called “Cioccolatone” by Italian watch enthusiasts because of its shape, the model was originally introduced to the market in the 1950s. It was available in several versions, the majority in yellow gold with either mechanical or automatic movements, as time only version or the more complicated variant as the present example with triple calendar and phases of the moon.
For a yellow gold "Cioccolatone" with calendar and phases of the moon see Ore d'Oro 2 by Jader Barracca, Giampiero Negretti, Franco Nencini, pl. D16.