Etiquette question: gift never arrived...

My friend and her mom gave me a $100 gift card for Williams Sonoma. The problem is, I got the paper card that the store gives out, and it's all filled out, but there's no plastic gift card.

The wedding was 2 weeks ago and I haven't heard anything from them (I figured maybe they'd find it and call me up to let me know that they had it). I'm not sure if I should say anything or just let it go

I would let your friend know that you didn't recieve the gift card. Maybe the store messed up and forgot to put it in the sleeve and she doesn't even realize that you never recieved it. If they have a receipt. then you could contact the store and have them issue you a new one (I think, most stores say that a gift card is like cash but I know from experience that they often have some sort of tracking # on the back).
I don't think there's anything wrong with contacting your friend-she spent the $$ on the gift for you which means she'd want you to have it--JMO!
good luck!