By "color/colour", do you mean colorized or toned or both? And if colorized, do you mean only when that process was done at the mint? You may want to explain more a bit about the scope when you start the thread.
"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz