No trades unless you have a classic RT or a Nummech VL Axe frame.
that grip is for rtp rails; you need one for classic rails (or, get an rtp / emag / tac-1 rail).
if miggosis has the correct foregrip, and
I think I may have the fore grip you are looking for. I will upload a picture of it tonight or tomorrow but it looks like it fits that rail and is red.