How would I go about selling a signed but sealed item?

[Toasty the Baker]

The item I'm talking about is the World of Thedas Volume 2 Exclusive Edition. It was sold on the Bioware online store and the first 500 orders or something were signed.

I want to sell it, but don't know if I should keep it sealed or open it. The only way I can prove its signed is from the packing slip that says it is the signed edition. Would that be good enough for potential buyers?

What do you guys recommend? Open it or sell it using the packing slip as proof?

-Toasty