Battery Came as 5020 mAh..

My battery's capacity is originally 5020 mAh. I thought this was a little under what others have? And now, only after 2 weeks of use, 4857 mAh (96%) remains.
Is this defective? If so, I think I'll exchange one straight away.

Unlikely that it's defective. Take it off electrical power until it drops into the 90% range, then plug it back in. It will not start recharging until it drops below 92%.

Lots of information here:

http://www.mac-forums.com/forums/showthread.php?t=97723