To my eye, Mike has really nailed the look of an original fowler. Studying original flintlock guns or images of them, you will soon get a feeling for the lock panel treatment of which you refer. This is perhaps even more obvious in European arms.
We as 'replicators' interpret what we see, and try to apply that information to the guns we make. I think many times, builders like the look of a contemporary piece, and emulate that, rather than going straight back to the source. This is perhaps why lock panels can be tastefully narrow and discreet, as in Mike's fine piece, or wide and pronounced. Even loud! One thing that we builders have difficulty with, is being brave enough to cut away the extra wood, wherever it is on the stock...the barre/ramrod web, the forearm, the cheek piece, the wrist, or the lock panel. On original pieces, I have not kept a ratio of narrow vs wide panels, but it is my impression that we should be shooting for the narrow look.
Nice gun Mike.