I have a feeling that the original Ep II Hero is made of tubes. If you can get it to bend right, I reckon the foregrip is two curved tubes over one another, the outer tube having the grips cut into it and the one inside creating the recess. I don't know exactly how the knuckle was done but, for me, the easiest route was to cast it in metal from a sculpt with the bend already. That had its own troubles but I think a series of bent tubes would work, too.