Odds mean little when it comes down to Nadal at RG. He could very well come unprepared and win the whole thing without dropping a set.
Odds anyways are made by form until RG if they are pre tournament odds. If it’s a final match between Rafa and Djokovic at RG - no matter what the starting odds in the tournament are - in this particular match Rafa is the fav. Just like in AO/W it would always be Novak being the fav against Rafa