I've a doubt, i thought about this when i saw the real name was GRD: What if those letters are the initials for a name like ''Golden Ranger Demolisher'' or some stuff like that? Maybe we'll get it on halo 4 if we kill that BOB elite at least a certain amount of time on Reach, or if we find all of his forms (I've heard that there are also different forms, like the White General, White Zealot, that sort of things). Another thougt i had, was that it could be a thing like if we find all those dolls on CEA, we'll unlock it on Halo 4.
-Sorry for the bad english, tho. I'm italian.