Will Apple replace my Magsafe Charger (under warranty) without my Receipt?

Unfortunately, my second power adapter died on me today (while finishing an essay due in 3 days!). I purchased it around 8 months ago so it's still under warranty. My problem is that I can't locate my receipt or any proof of purchase. I'm planning on scheduling a meet with a genius, but will Apple know when my purchase was made without the actual receipt?