The red fabric patches over the gun ports were doped in place to keep dirt and grime from entering and if the guns were fired they would be shot through and then replaced as necessary. If you do a search on Google for "Spitfire Walkaround" you will find many, many detail photos online. Much more than you could ever acquire in a hundred books. Just make sure you are looking at the correct mark of Spitfire when deciding on which details to duplicate.