It could easily have been a return from another store, or a return on a receipt using a figure someone didn't want in place of what they did want... It's hard to say.
It could just as easily be that you missed a case of figures... Obi-Wan is one who tends to sit from that assortment, but it'd be odd not to see all the other stuff from it that tends to sit. *shrugs*
WM is the place to be for 4... I have seen it in bulk at this point, except Jango and Anakin. All the rest, tons. Someone bought me an extra Senate Guard tonight that's been hanging out for about a month now.