Note that for the first year of the North American padded dash and electric oil and temp gauges (Mk2, 1967) the schematics show something different. For a start instead of a light-green/green wire coming from the instrument voltage stabiliser to the first gauge (fuel) it is shown as a green wire. This wire then daisy-chains to the oil gauge as a light-green/green, then daisy-chains from there to the temp gauge as a green again. After this year only the fuel and electric temp gauges are fed from the stabiliser, the oil gauge is fed with a full 12v (but only until the start of the 72 model year when it reverted to a mechanical gauge, albeit of the single rectangular type). Apart from the different wire colour the oil gauge being fed from the stabiliser could have been required if a non-stabilising sender had been used for just that year, but the Parts Catalogue doesn't show that. Certainly the later sender was an industry-standard device which included its own stabilisation function as well as pressure transducer. Therefore it either was connected to the stabiliser, erroneously, or it is an error on the schematic. With two separate 'pulse width' stabilisation circuits in series I would expect the oil gauge to read low, meaning that perhaps it is just a schematic error.
North America reverted to a capiliary oil gauge in 1972 for the remainder of production.
UK always had a capiliary oil gauge, and the temp gauge only became electric in 1977.