Purchase codes (license keys) are not included for plugins which are bundled into theme. It’s because of Themeforest license & agreements. This applies to all themes of course. However, there is no need to use this code because the plugins are fully functional without it. If you want, you can read more details about this on Envato forum:
Comments
we are sorry but what exactly you can not update? Product license? What does it mean?
http://themeforest.net/forums/thread/dont-work-my-purchase-code-stardust-w-revolution-slider/186285