From another forum posted by the manufacturer:
Auto/Wardrobe is an average of 1:288. A few cases will see a second card, but not very many in the grand scheme of the print run.
I was hoping for more than a few cases with more than one. This is going to be one expensive set to collect.
But at least it should hold value.
This is from the same person who gave the information about the wardrobe cards having a high likelihood of two per box.