I saw a Delta 767-200 in the newest colors in ATL on my trip to LAX on October 27, 2001. According to Riz Maher's website (http://www.geocities.com/rizmaher/delta/deltaindex.htm
), which was last updated on August 22, 2001, none of the 767-200's have been painted. So it was between August 22 and October 27, if that helps any. Although the one I saw was (I think) N111DN, while the one pictured is N113DA. So, if I am correct, that would mean that two of them have been painted.
Hope that helps!