IWC Mark XI variations in dials

According to Horological Journal January 2004, there are a few versions of IWC Mark XI. My guess is that there are more than 4 versions. Even within the 3rd versions with the circle T, there are also variations in terms of the hook ''7" and normal 7, etc. In addition, there is also the service dial with the T SWISS T as well as the black dial civilian versions. As for the case back engraving, there are also many variations as well. 

Source : http://www.gregsteer.net/IWC/Mark_11/mark11a-en.pdf

According to the 'Man is Not Lost' article about the Mk 11 navigational wristwatch (Christian, Koenig and Steer), IWC sold, beginning in 1949, over 8,000 Mk 11 units for military use- 7,400 to the RAF, 600 to the RAAF, and an undetermined number (thought to be ~600) to other Commonwealth Air Forces like the RNZAF and SAAF. Included in this last number of ~600 were an undetermined number of Mk 11 units purchased by civilian airlines including BOAC.

When in 1973 the RAF introduced the Mk 11's successor, IWC then sold genuine civilian Mk 11s - 500 units in 1973 and another 500 units in 1983.

IWC Mark XI uses the famous IWC caliber 89, 17-jewel signed manual wind movement, hack setting, adjusted to 3 positions, with shock protection, round screw back case (36mm in diameter) with anti-magnetic zero gauss cage and dome. Fixed lug bars, original signed case for military and unsigned back case to distinguishes this civilian version from the military one. The civilian version is harder to find than the military one as only 1000 units were produced. I have managed to find the second and third versions as below. 

Second version is without the circle T and without the arrow and it's perhaps the civilian version (but it has the NATO engraving at the back). Watch may have been recycled during a certain period before it was decommissioned) We have to remember that MOD watchmakers were not thinking of us collectors but rather of ensuring a "tool" entrusted to them was put back in service and was fully functional and in good repair for re use.

 

Third version is with the circle T.

Just found this photo of a back case where the watch was reassigned to GAF  

Government Aircraft Factories (GAF) was the name of an aircraft manufacturer owned by the Government of Australia based at Fishermans Bend, a suburb of Melbourne in Victoria. It had its origins in the lead-up to World War II, during which it was known as the Department of Aircraft Production (DAP). In 1987, GAF was reorganised and renamed as Aerospace Technologies of Australia (ASTA) then privatised. ASTA subsequently formed the nucleus of Boeing Australia

http://www.mwrforum.net/forums/showthread.php?46561-GAF-IWC-Mark-11&highlight=IWC+Mark+XI

http://www.mwrforum.net/forums/showthread.php?37173-interesting&p=153057#post153057