I wouldn't trust info on this page too much. The color reference on the KLM clearly is wrong as it gives the same color codes for all details.
There's at least two "shades of white" on the real KLM livery:
White as in "white" (no clue which exact shade):
- v.tail
- titles
- rego
- door outlines
- winglet inner sides
...
Pale grey (again, no clue which one):
- belly
- engine nacelles
- winglet outer sides
Here's a quick reference using one of
Dirk Grothes fantastic photos (always good for referencing)
I added two colored bars for better reference: