Enable lock screen widgets, 4.4.2 Kitkat on Samsung Mega 6.3 LTE
Samsung's TouchWiz UI does not allow you to add lockscreen widgets in Kitkat as far as i know. My Galaxy Note 10.1 has the option named "lockscreen widgets" under settings, but its not anything like the stock Android Kitkat concept.

You have to install a custom ROM if you want that functionality.