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
http://themeforest.net/forums/thread/dont-work-my-purchase-code-stardust-w-revolution-slider/186285
All necessary details about Revolution Slider update you can check on http://forum.muffingroup.com/betheme/discussion/5/how-to-update-revolution-slider where we described everything.