The target has not changed once in the last four Axis & Allies games - the ONLY reason they have had different colors in previous editions is that they changed them to match current standardized colors.
For example, the much vaunted Axis & Allies Pacific: The color change in it was made from Red Japanese to Orange Japanese to bring the colors into standardization with the Axis & Allies color scheme. The US and UK were left unchanged, so much so that I can use F6F Hellcats from Pacific.
I don’t see what is so difficult to understand about this concept - after some initial changes, Avalon Hill has standardized the colors. The second edition of Axis & Allies Europe has the 1942 piece colors, except for Germany, which is still gray and not black (that change came about in A&A Battle of the Bulge). The second edition of Axis & Allies Pacific also has 1942 piece colors, with the exception of China, which has now been standardized in A&A 50 and A&A Pacific 1940 as lime green.
I should know a little bit about this subject - while not being Imperious Leader in my games collection, I have about 3-4 copies of each version of Axis & Allies game released, including the Nova Games version. I can trace exactly how piece colors have changed from edition to edition, and some Avalon Hill missteps (greenish UK in Revised?!). However, that is old news, and one should be able to draw some lessons that for the past four years colors have been exactly standardized and every single game in print has the same color scheme.
As to the German color, some of you need your eyes checked. The current Axis & Allies German color has a RGB value of 10/10/10 (in other words, indistinguishable from black to the human eye). I have perfect color perception - the closest I can identify the Spring 1942 German color is to a RGB value of 3/3/3 (pure black).
I’m sorry for such a long post - it is just that looking at an old copy of Axis & Allies Europe tells you nothing about the current state of pieces and colors in the Axis & Allies franchise.