Greg,
That's a nice fowler, I really like the curve of the bottom of the butt-stock. I dearly want to build a fowler of similar genre, representative of a gun my ancestors from Mass. might have carried during the rev war.
I'm about as far from an expert on fowlers as you can get, and not a great builder, but I will add a few comments since you asked. I happen to be looking over my current build with an eye towards graceful lines, so some of your build caught my eye.
I think you did a nice job on that lock. The shape is pleasing to the eye with the curve on the bottom. I think the moulding around the lock panel could match the lock better. The nose moulding seems angular and contrived. I'm away from home and can't reference my copy of Grinslade's book, so if that is copied from an original, disregard.
I also think the moulding at the bottom of the lock where the lock plate curves up could/should follow the lock plate and maintain a consistent width. On yours it seems to widen as the lock plate narrows.
I also think that the sideplate could be more graceful. The curves at the tail are segmented instead of flowing. Similar thing around the rear lock bolt.
I happen to be smoothing out the background from my carving and moulding lines on my current build, so have given a lot of thought to that. I think you could feather out the background further and smoother around your forestock, and lock moulding.
If anything I have said is contrary to what is found on original fowlers, it is due to my lack of knowledge, so disregard.
I really like the gun you built and hope to build one someday, so these points are nit picky and happen to be what is on my mind right now.
Cheers,
Norm.