Ward, I hate to sound dense, but what do you mean by "watered"? Also, I enclose herewith
a photograph of the reverse of the lock. It does appear that the barrel is only held in place by one screw, through its tang, so it might well be relatively easy to remove the barrel for work; there is, however, another screw on the underside of the bolster around the lock, perhaps for holding the trigger mechanism in place? Still not been able to get a decent shot of the lockplate, unfortunately.
However, regarding the lock, I remain worried about dismantling that. I'm very good, as you can probably tell, at finding things about which to worry!
Jim, I hadn't really thought of it that way. It had occurred to me that the markings were important, of course, but the aspect of assumed "transfer" of the original weapons' capabilities, and the strength of the forces armed with them, had not. I sort of assumed that the markings were treated much like a proof mark, i.e. as a sign of good quality of manufacture. It is, I agree, good to know that such comparatively ancient weapons as these are still in use to this day; if nothing else, they and the people who make them represent a fascinating insight into the pre-industrial processes of manufacturing, and their products, almost unknown in the modern Western world.