I've used plugs too, to fix a screw up. On my latest Hawken, I ran the drill out through the side of the forend not once, but twice, and repaired the damage with plugs. One is really noticeable, and the other practically disappeared with the staining and finish.
On a previous occasion, I cut the butt stock of a rifle for the butt plate, and then realized I was an inch too short - cripes!! So I just glued the piece back on, and since it was a single band saw cut, it mated perfectly. You cannot see the joint to this day.