Do i need a proportioning Valve?

Ok another question! I got a reman master cylinder. The front of the master is 9/16-20 thread and the back one is 1/2-20 thread. I can not find a 9/16-20 to a -4 AN fitting. Anyone know where to get one? Also which is the front brakes and which is the rear brakes? Thanks. Hope I dont sound dumb.