the epic edition comes with a code that you input to get dlc for bulletstorm. once the beta is open you start the game and go to an option on the menu for the gears of war 3 beta. in other words no. you need to buy the ee even if the code comes with rental which it does not.
YOU need the disc and the code to get gow3 beta access. this is not the only way to get into the beta but the only guaranteed way!