17 R1, Mini Display card

Recently picked up this Alienware Laptop [Alienware 17 P18E/P18E001] at a swap. I was upgrading the memory and noticed that a card slot on the memory slots 1 & 2 side was missing. According to the manual it is the mini display card slot (DMC H18). Had no issues booting and using the laptop before deciding to do the memory upgrade, but am wondering if this is a necessary componet that I should try to find and install. If so where would I find one? I've had no luck so far finding one where I've looked online.