Can't find this in my book but when bees fill and cap a cell with honey do they tend to cap it flush and when they cap brood build it up a little. Just checked my hives on Permacomb and noticed flush honey and protruding brood. Thought I read it was the other way around but can't remember.
Worker brood is slightly (only slightly) domed. Drone brood is extremely domed. Honey is level.
Also honey caps are white and a bit shiny (satin finish). Brood caps are yellow and more flat finish.