I think I see what you see if you're talking about the mark on Abes chest. It looks about the same size and shape of a knee. I don't know if you're familiar with this site. http://www.coppercoins.com/advsearch.php You could check there and see if you can find a match. BTW, welcome to C.T.!
d.t. thank you for your comment. Went to coppercoins and there is nothing there for 2004 http://www.coppercoins.com/lincoln/dateguide.php?date=2004
There are so many of these minor varieties and just because one is not listed on coppercoins, its meaningless and the coin still could be a variety. That said, I cannot see anything clearly enough from the photo to say either way.
