Fuel Pressure Regulator! When??

Two totally different looking pumps, different part numbers. Mancini has them as well. I don't know, from what I've seen they are in no way the same. The Mopar has an mp part number the carter has a carter part number. Not trying to be difficult, but I just don't see how they could be the same. http://store.yahoo.com/chucker54/mechanical.html