The Palace seems to have the same opinion as me on this. Their information advisor said this in an article: "The King and the Queen will follow the recommendations of the Norwegian government in the question of attendance at the Olympic games."
Aftenposten.no: Åpner for kongelig OL-boikott (Innenriks)
At the same the red-green politicians ask the King, the Queen and the minister of culture not attend the opening ceremony. The Prime Minister, on the other hand, who is also from the red-green political alliance, has expressed doubts on the effect of boycotting the opening ceremony:
Rødgrønne politikere ber kongen droppe OL