Hi Jay,
I think you are fine. Here are some pictures of an original English gun with a large round faced lock.
When I cut moldings for these locks, I bring the edge almost right up to the edge of the lock and then in the final shaping, a couple of swipes with sandpaper backed by a flat wood block creates the barely visible flats. I urge you to shape your fore stock before going any further on the lock panels. Also, it looks like the wood is still high around the lock, so when you file, scrape, or sand that down flush with the edges of the lock, your flats will reappear.
dave