We honestly do not know whether the gold disk on the top left of the card came with it or was put there by the sender, but based on a small notch in the back for a tab to go in, we think this is how the card was made.  No guarantees.  Mailed in 2013 with two different stamps, blue trilingual Air Mail sticker, and the “Taipei 101” irregular shape that you can see.  Grade: 1