Sure. His name would be helpful.
Almost all of the Norwegian commandos got the Norwegian War medal for the campaign in Walcheren. To that you can add the Norwegian Participation medal, and king Haakon 70 years jubilee medal (if your grandfather was part of the Norwegian army in UK in August 1942).
From UK he would have gotten the 1939-45 and France & Germany stars, since the Norwegian commandos served under British army command. Technically he would also get the British War medal for WW2, but this was not awarded to Norwegian who got the Norwegian Participation medal, due to overlapping award criteria. Finally he might have gotten the British Defence medal, depending on his service time in/outside operations in UK and mainland Europe.
These would normally have been the default decorations to a Norwegian serving in the said unit and battles. He might have gotten some individual medals for bravery or merit, but it takes his name to see if that happened.