looking for a picatinny mounted rear ghost ring sight

the shotty im looking at already has a high fiber optic front sight and a rail on the receiver. im thinking that i can get a rear rail mount ghost ring sight and they might line up ok. if not i will try my magpul mbus rear which would be a little higher.

so my ? is does anyone make a rail mounted rear ghost right sight? i would prefer one that has the rails on the side for protecting the sight.

thanks for the help