Is not exactly as should be looking on schematics you point a weak part of icon
. for my defence I can said that I try model pointed shape o fuselage.
Is hard with small number of pixel have exactly correct shape. That is other variation proposition meaby closer to correct shape?
If you will be happy I can repaint to that fuselage rest of the icons.
Generally based on your icon on beginning I rebuild some lines on wings and add a fuel tanks valves were painted in red on all British aircraft and also not always but often on American. Engine is slightly streamlined more like in your Spitfire icon with exhausts and fuselage which I try to model to be like on schematics but as you pointed that isn't easy task.
Changes made in original icon
based on plans
http://target4today.com/Simple-Multi.../p51b_1_3v.jpg
BTW great page with different aircraft blueprints
http://target4today.com/Simple-Multi-View-Plans/
In case of Mustang always come to my mind citation from Reichsmarshal Hermann Göring
"The day I saw Mustangs over Berlin, I knew the jig was up"