the hex union under the fuel pressure regulator is the fuel return line to the tank. the hex union on the right hand end of the fuel rail is the fuel feed from the fuel pump.
Ermm, this third pipe is confusing me. There is no fuel pipe connection to the inlet manifold. If its another hex union with a stiff plastic hose attatched then thats the vacuum line that goes between inlet manifold and brake servo. If its just thin guage rubber hose with jubilee clips it will be coolant hose. If its meduim/thick guage rubber hose and a large stub on the manifold it connects to the arse end of the Idle Control Valve.