they are not modified or anything - its a different but standard design, the pressure discharge valve and suction control valve on the rail and pump are different too for countries with different fuel specification. The same items on the JDM "yateem" hiluxes/LCs were not specced for Pakistan/India diesel fuel.
if you have an old 1KD and want to spec it to your country then you need to change the PDV, pump, SCV, injectors and rewrite the ECU.