I happened to still have the box laying around, went and checked to see if I had more than one code and I did not. I had only a product registration code on a paper insert inside of the metal collectors case. So to be honest, it is likely a scam if you are only purchasing the product code. I highly doubt anyone would buy a collectors, hold on to it for 2 years without using the code, and then be willing to part with only the code instead of the whole package.
The only way in my eyes to verify whether or not the code has been used, is if the plastic sheath around the box has not had the clear round stickers removed from the top and bottom. There is absolutely no shrink wrap involved with the packaging.