I have a bushmaster m4 that I wanted to put a fold down front sight on. I purchased a m4 that has a front sight "base" basically to hold the hand guard cap in place. I think I have found a front sight rail that fits over (?) the front sight base (with the bayonet lug). I cannot determine if the unit I am buying does what I want, as the photo shows the unit "assembled". Is the front sight base removable? I see taper pins that hold the base tight, but I cannot determine if the base is part of the hand guard cap, or worse, integral to the barrel The Thermoset hand gaurd is removable, but it has a spring in it and it is recommended that a "buddy" help you with this step. So, I am afraid if I remove the cap guard, I will have the thermoset hand guard "explode" apart on me? True? Can I drive the taper pins out and slide the "base" off?