It must be one of the only cars with such wiring ?
Maybe just due to it's age ?
Typically on a modern car, the only shielded wires you'll find are VR sensors, NB Lambda and MAF signal.
All of which are essentially high frequency/oscillating signals
Bog standard 0-5v voltage that are fairly linear in operation are never shielded. Even rotational hall signals like crank, cam, wheel speeds etc arent shielded in most cases