I wasn't going to say it JP,but since you did
I was thinking about replying by saying " would you really need a blank backed card to complete a back run"?
It would be way cool to add it to the back run,but don't know if it would be "necessary" to have to meet your goal of a complete back run.
Good luck though,I hope you and the seller can work out something that satisfies you both!!
Sincerely,Clayton