This is the first and only genuine antique "gun hammer" I have ever seen, leading me to believe they must not have been common.
Something they called "gun hammers" were frequently advertised.
The South-Carolina GAZETTE
October 29, 1753
CHARLES-TOWN
B & NEYLE, have just imported, in the Alexander, Capt. Carking, from London.... black Pepper and Spices, F and FF Gun powder, all sorts of Shot and Bullets, very neat fowling Pieces and trading Guns, Pistols, gun Locks, gun Hammers and Worms with sockets, powder flasks, cartouch Boxes, shot and bullet Moulds, bar and [sheet] Lead, silver and mourning hilted Swords, cuteau and sword Belts, sword Blades, fencing Foils...
The South-Carolina GAZETTE
July 4, 1754
ARCHIBALD & RICHARD
CHARLES-TOWN
HAVE just imported, in the Anne, Capt Elmes, from London ….brass candlesticks, single and double gun powder, bullets and all sorts of Wilson's neat fowling pieces, gun hammers, powder flasks,
The Pennsylvania Gazette
September 18, 1755
Just imported in the ship Myrtilla, Richard Budden...fuzees, fowling pieces, gun hammers and screws,
The SOUTH-CAROLINA GAZETTE
May 6, 1756
Location: CHARLES-TOWN
.... snuff boxes, shoes and knee buckles, lancets, gun hammers, snuffers, wafers, sealing wax and quills, ink powder.…
The South-Carolina GAZETTE
December 8, 1759
....mohair and metal buttons, Wilson 's fowling pieces and brass mounted pistols, powder horns, cartouch boxes, gun hammers, curry-combs and brushes,
The South-Carolina GAZETTE
June 13, 1761
CHARLES-TOWN
... large and small powder flasks with springs, steel spurs whole and half hunter, twig whips, spatterdashes, neat light fowling pieces, inferior ditto, socket worms, gun hammers, cartouch boxes, belts and hangers, penknives,
Spence