If RAK follows the Semtech reference design then the LEDs are connected to GPIOs on the SX1302 rather than radio signals as in previous designs.
please see
If this indeed means that there’s no way for the SX1302 state machines to directly operate the LEDs and that must instead be done by host software (meaning host schedular delay), then that has the unfortunate consequence of meaning one can’t use a scope probe on the gateway transmit LED as a reference for checking node receive window timing, making such a gateway a bit less desirable as one’s only platform if doing deep development on node firmware.