Beowulf is not in anyway selfish in his desire for fame. This is because Beowulf has risked his life on several diffrent occasions in order to save Herot from Both Grendel and Grendel's mother. Beowilf's unselfishness is truly testified when he ventrues deep into the swamp where Grendel's mother lives in order to kill her and save Herot. In addition, Beowulf is not even protecting his home land fro mevil. He is risking his life in order to save a foriegn land of Herot from evil when Beowulf lives in Geatland.
It is clear that Beowilf would be willing to risk his life in order to achieve eternal fame. This is because Beowulf mentions that, ("fame after death is noblest of goals." lines 1388-89.) Beowulf believes that risking your life in order to save a group of people is the ultimate achievement. A person who was selfish about fame woud not in anyway want to risk themselves to order to save people from a foriegn country.