Huvius - It is interesting that your full cock safety is at the front. According to Wal Winfer the single shots had front and rear "stalking" safeties both acting at the half cock position

Alexander Henry, like all gunmakers, bought in locks (often from Joseph Brazier, the premier lockmaker of the era) so a pair with full cock safeties may have been bought as a one (or two) offs

Also the flatter (earlier?) hammers are very nice

Is it for .577 - 3"? or 2 3/4" or 2 1/2" case?

A full set of pics would be most appreciated

Tony