What do you mean by "handgrip"?
Do you mean the pistol grip, the forearm, or the carrying handle?
If you mean "carrying handle", the item that holds the rear sight: if you plan to get into optics, get the A3 upper with detachable carry handle. If you don't plan to use optics, and want the rifle for self-defense or "tactical" competition, get A1 sights. If you plan to use the rifle for static competition (High Power, etc), and don't want optics, get the A2 sights.
Does that cover you? Let me know if you meant something different.
-MV