There are no 81 doubled dies but i seriously feel i have one. Its clear though i am no expert. My 1973 looks to be one in comparison to varietyvista. Mind seeing for your self?
73D I think has one listed DDO...a bunch of RPMs. from the pictures, I cant see anything that appears to be a doubled die. I can see MD and some evidence of a worn die near heading out toward the rim. Doesnt mean it isnt though as its just my opinion.
Yes, all environmental toning. Cents begin to tone almost as soon as they enter circulation, once they have been cracked from the rolls. When you find an older coin in very nice red condition, it's likely because it was stored some way that prevented toning until the owner sent it back into circulation. Zinc cents, 1982 and later, will deteriorate much faster than the bronze cents made before 1982.