At least you made it public that the items are not in hand. That would be the best way to proceed.
There is no way anyone could know if you have the items or not (unless you admit it), so you obviously COULD sell them before you receive them, but it is ill advised. As noted, you run the very real risk of not receiving the cards or having them arrive not as advertised and they you have to deal with your buyer, making yourself look bad.
I don't even like talking about items until I have them in hand, such as in the recent pick-up thread or such. Occasionally, I have won something on ebay and it either didn't arrive (lost, seller claims they didn't have it anymore/can't find it) or it was damaged and I had to return it. It is bad enough not to get something you really wanted, but it would be even worse if I talked up the item and then it didn't arrive!