7260 wifi card differences

[turomini]

Hi,
So I was looking to upgrade the bluetooth in my T420s to at least 4.0 with low energy. It looks like I could just upgrade the bluetooth card, but I realized upgrading to a 7260 wifi card will achieve the same.

So I was looking at the 7260 cards on ebay and noticed there is FRU 04w3815 and 04w3814.
Is there any differences between these two?
It looks like I can get 04w3815 cheaper, but the 04w3814 is more common.