modified Bushmaster Bullpup

I am looking to put some better sights on my bullpup, and need some info. My idea is to remove the carry handle and modify the cocking lever to the left side of the gun. I want to install a long weaver base and install either an ar-15 a-3 carry handle or a flip up sight, in conjunction with a detachable front sight. My question is, on a flat top ar, is the rear base the same height above the bore as the one on the one for the front sight?