yes, the minecraft world generator works the same, but each modpack also adds its own parts, like tekkit volcanoes/oil or the bunkers in voltz..
i found a basic voltz bunker seed:
ignoramus
dont ask why i chose to try that, i dont even know..
spawns you in a jungle biome with a cobblestone bunker, not much in it, but its a good starting place and has some redstone/mossy cobble
haha lol.. i'm the ignoramus... thats a normal minecraft thing lol.. guess i haven't played with that many 1.4.x seeds yet.. *facepalm*