@c23, it would be helpful for you to post a link to this auction, but I would say in general that all two headed coins are post-mint constructs (not mint errors). Typically, these so-called Magician's coins are created by either sanding two coins down and sticking them together or hollowing out one coin and placing a reduced diameter, second coin in the resulting pocket.
"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