A 1990 registered 2WD would have ambers, and be identical to an '89 2WD.
The '1990 facelift' included all the 4x4 changes. There is no overlap with smoked lights being used on 2WD cars etc.
That's my belief as well.
My 1990 2wd had ambers from factory, but when I bought it had smoked.
You have to remember late 2wd's probably had their light changed AS SOON as the 4x4 was out (could have been within weeks!!!), to make them look like the latest release of the car.