From the appearance of the engraving (nice photos, by the way) this is a best work gun. "Best work" was roughly a standard throughout the trade. Best work boxlocks are considerably more rare than are best work sidelocks due to the higher fashionability of sidelocks. Best work BL's are of the same quality as best work SL's (that statement may well start an argument). Interestingly, the various factors of a gun would usually be all the same quality grade of work. That is design , materials, workmanship, and embellishment would match for quality. Nice find. Enjoy.
DDA
