The numbering found on small pocket pistols are nomally "1 " and "2" as they where normally ordered in pairs. Addtional numbering is seldom seen on pocket pistols, particularly if they are part of a gift of luxury weapons to dignitaries.

This pistol is numbered 16 in the same place as the pair numbered "4", and the turnoff barrel on this pistol is numbered "1". A second identical pistol has existed, and probably also a case with tools.

Maybe the twin to this pistol is in a collection somewhere. As this pistol "16" is for sale in Australia if the woner of the twin numbered "2" want to have a complete set.

The photos below are from the website of Michael Barnett: "Antique Guns. 

Many of Boutet’s pocket pistols carried ultra-short turn-off barrels, this one is only 25mm with a 13mm bore, engraved with multiple bands of geometric and floral engraving.

This pistol demonstrates several of Boutet’s innovations; concealed button operated safety locking the hammer at half-cock and concealed frizzen spring all attest to the quality of this pistol. The lock panels are fully signed in beautiful cursive script surrounded by foliage Boutet Directeur Artiste and MANUFre Versailles on the other.

Boutet’s deluxe grade pocket pistols have a unique feature – the fitting of the stock to the frame is not the usual right-angle box-like fit, it is a complex wave-like pattern requiring great skill.