The serial number no longer exists. I guess Hasbro is tired of trying to keep track of all the current variants we're seeing. The only way to tell the difference between figure versions is by the differences in the figure or card or even bubble, tape and/or wire. The PN numbering system seems a bit strange too. They list one on the bottom of the bubble and one on the back of the card. Both of these numbers are different but on the same figure and they are this way on every variant (i.e. I compared my Bloody Luke, metal peg Luke & fleshy peg Luke and my Luminara with 'removable cloak' text, with 'removable' covered, with both covered and the reprinted insert with it deleted). For someone who composes checklists, this is definitely a bummer. But, it's the way it is. If I find anything further, I'll let everyone know.