Sims 3 Ambition download doesnt contain a serial code?

I bought and downloaded The Sims 3 Ambitions today from origin. I started to install it and it asked for a serial number. Everyother game I have purchased on origin had the serial number when I clicked on info in the game tab. Ambitions did not, I looked on my order confirmation, no serial number. I'm kind of at a loss, am I doing something wrong?