Here are a few points to remember about British export gun locks...
1st. Literally millions of them were made. There is no way millions of gun locks could be made in two or three Black Country villages over a period of 30 years without a massive amount of specialization. I am certain Ashmore, and ALL of the names we see on these locks were contractors, buying in parts from specialty suppliers like cock makers, plate makers, pin (screw) makers and fitters. They had to have adopted a very large degree of specialization and the locks themselves were probably more interchangeable than we customarily think and, specialization to this extent limits flexibility so older styles stayed in use far longer than is generally thought. The individual gun maker making a lock from scratch is largely a fantasy... if it ever existed, it was an obsolete process by the beginning of the beginning of the 18th century. Because the B'ham lock makers were able to produce so many, for so little cost, there was no incentive for American civilian gun makers to do so. Our military locks were made as part of a government subsidized program to achieve independence in arms manufacture as a matter of national security. It did not save money.
2nd. Virtually all of our dating criteria are based on "best quality" London guns which are much easier to date (because the makers are so well known) and, to a much greater extent than the provincial and export market, were fashion driven. That a new style is seen on a London gun that is readily dateable has relatively little to do with what was going on outside that market.
3rd. Locks were sold by the dozen in a very wide variety of quality. Based on William Ketland's wholesale price list (the only surviving document of it's type I am familiar with, written out in the summer of 1812) they ranged from 17/ per dozen, for the cheapest lock without internal or external bridles, to 145/ per dozen for the best quality with a waterproof pan and sliding safety. All of these were available simultaneously from the same sources so minor advancements in mechanical development are almost meaningless from a dating perspective.
The wholesale price for the cheapest export fowler was also 17/ so a dozen of the cheapest locks cost the same as a cheap gun while a dozen "best quality" locks cost 12/ each. These prices are in shillings in 1812. I don't have my notes on this at hand but in 1812 but the British pound reached it's lowest value vis-a-vis the dollar for the entire 19th century so these are about the best prices ever seen in the flintlock period.
By the late 1820s, percussion was already overtaking flint... again, this happened much quicker than we generally think, I suspect because many American collectors concentrate on the "frontier" where, as in the provincial gun market, older styles held on longer. But... gun locks were largely being exported to the east coast where the demand for percussion guns had nearly eclipsed flint by the late 1820s so, while some demand must have lasted for the older types, it was on the wane quite early and statistically, the vast majority of flint locks almost certainly pre-date 1822-23 which is when large quantities of caps start to be regularly advertised.
