Yes that's right - if you're using a 1920.GW from a 1.6HDi you need to swap wires, the pinout is different.
Can't remember which wires need swapping though.
EDIT: Because I'm really good to you, just went and found diagrams -
1.6HDi
1 - Ground
2 - Signal
3 - +5v
2.0 8v HDi
1 - Signal
2 - Ground
3 - +5v
So in answer, yes, 1 & 2 need swapping.
Can't remember which wires need swapping though.
EDIT: Because I'm really good to you, just went and found diagrams -
1.6HDi
1 - Ground
2 - Signal
3 - +5v
2.0 8v HDi
1 - Signal
2 - Ground
3 - +5v
So in answer, yes, 1 & 2 need swapping.