The 350-year-old pistols were in the Rothschild family's collection in Austria until 1939 when they were seized, along with artworks, by the Third Reich and stored in salt mines during the war.
It was in these same salt mines that the Nazis hid 6,000 other works of art, as retold in George Clooney's recent film, The Monuments Men.
During the 19th century, when it was at its height, the Rothschild family is believed to have possessed the largest private fortune in the world.
After World War II the pistols were repatriated to the Austrian state museums where they remained until 1999, when they were returned to the family.
They were made by Pietro Manani circa 1660-70 and feature a chiselled decoration which includes bearded grotesque masks, monkeys playing cornets and various monsters.
"There can be few pistols with a more interesting history than these magnificent survivors of centuries. They are artistic and technological marvels of their time and remain today a window into the superb craftsmanship of the past," said David Williams, Director of Bonhams Antique Arms and Armour Department, in a press release.