Neither did I see such interesting markings on a Bf109, and centainly not in connection to Günther Rall. Thanks a lot for your help, Sinisa.
By the way, Ubben had an interesting career, starting as a sailor in the German Navy and ending as an appointed commander of JG2 at the time of his death on the Western front in 1944 with 111 victories.
In 1941 he attacked Allied shipping in Southern Greece, gained some hits on the battleship Warspite and claimed a British Torpedo boat sunk.
http://www.luftwaffe.cz/ubben.html