That book you ordered has several shots of 71 Sqn Hurris and some profiles. One of the profiles shows XR-T, Z3781 which Dunn used to destroy two Bf 109s in July '41. I don't know if this was actually his assigned aircraft or not but it is often attributed to him.
It also has one photo of Dunn's Spit taken after he returned from his last mission and a profile showing the starboard side of the same aircraft.
I looked in the Osprey book 'Spitfire Mark I/II Aces 1939-41' and there is the same photo as seen in the 'American Eagles' book as well as a profile of the port side of the aircraft.
The picture in Cleaver's article of Dunn by a Hurri may not actually show his aircraft. Dunn was credited with two kills on his last mission to make him an ace. (The subject of much controversy over the first twenty or so years following the war) There are four kill marks next to the eagle, and if he only had three kills up until that last mission then this would, at first glance, seem to be another Hurricane. However, pilots often included probables and/or damaged aircraft in their scoreboards. So it
could be his Hurri and it's my gut feeling that it is his, but I really dunno fersher...
The Battle of Britain Memorial Flight painted one of its Hurricanes in the colors of 71 Sqn sometime back and it was XR-T that they chose to represent. I'm sure you know the pitfalls of using a restored aircraft as a reference but sometimes it's all you have. Anyhoo, you can see several shots of this aircraft in this scheme (as well as in another scheme) here...
http://www.airliners.net/search/photo.search?regsearch=G-HURI&distinct_entry=true
Fade to Black...