My information is that Purdey developed a functional mechanical single-trigger in 1890; Holland & Holland in 1891; Boss & Co. in 1894, with a perfected design by John Robertson and William Adams -- the pinfire game gun was history by then. Most guns at this point would be hammerless, but a few clients might have preferred external hammers, but were willing to try a single trigger? If anyone can refer to a published image, that would be useful.
The recoil-activated single-trigger came much later, with Val Browning's patent in 1940.
If someone has volume 3 of Crudgington & Baker's The British Shotgun, there might be more detailed information on who came up with the first single-trigger mechanism on a double shotgun.
That pistol is quite interesting, AaronN!
As to gun decoration, Mark, to each their own, I guess. I still marvel at how a scrappy Mediterranean weed ended up being the inspiration for most gun engraving.
