The crest is probably that of either Cracroft, Crawley, Cross or Crosse.
William Boss was apprenticed to his father of the same name in about 1801 and worked with his father for Joseph Manton. William (2) was the elder brother of both Fisher and Thomas Boss, later also gunmakers. William (1) died in 1809 and his son William, aged 27, left Manton to establish his own business at 9 Crown Street in 1814. William left Crown Street in 1817 and no further record of him exists beyond that of him renting a room from his brother Thomas in 1819.
As the first independent gunmaker within the family William Boss (2) can be considered the principal forbear of the present London gunmakers Boss & Co.
This hitherto unrecorded pair of duelling pistols is almost certainly only the third known surviving example of firearms by this maker; they are also the most elaborate and not suprisingly compare well with pistols produced by the renowned Joseph Manton. Another pair, in their original case, are in the Royal Museum of Scotland.
See Donald Dallas, Boss & Co. Best Gunmakers, 2nd edition, Shrewsbury, 2005, pp.13-18.