I'm assuming that you got the quest to bring back something 100% t'rang. When you give the hand to Balbrack, he says something like, 'yuck, you keep that slimey thing' and then praises you for getting it. Hang on to the hand, because it may be useful somewhere else (where only a t'rang hand can get you into).As for Mt. Gigas, you don't need to give balbrack the alliace letter in order to get into there. Once you have a level 3 security pass, you can access that area.