Intersting, and fishy at the same time. If the numbers match I would contact the Police. Did the guy who lost it report it stolen to Police or Ins. Co? Laptops are covered by most Home Owners Policies so he would have reason to claim it.

I would not return anything until payment has been returned to you. Also check the ebayer's feedback (both seller and the guy that contacted you)

Previous Owner of 00 SVT Contour #1077/2150 95 Contour SE '01 3L