Gas path is correct.
The APU fuel line picks up fuel from the engine fuel feed line, not the left tank. The APU DC pump picks up fuel from the left tank and outputs to the engine fuel feed line. Any pump or tank could be used to feed the APU providing the crossfeed is open. The key point is to pull the circuit breaker for the Left Aft Boost pump especially if the left tank is empty as it can't be controlled from its own switch when the APU is running.
