Rahul is genuine.
1) He had a problem with Shweta's cooking. He told Dolly that he would support her and he did even when noone else like Veena did. That is genuine.
2) He had a huge problem with the boycott issue. He believes it is wrong to isolate a single person and I completely agree with him. He told the guys that even though the fight was wrong, he was not going to support them on isolating someone. That is genuine.
3) When everyone was all over Shweta because of her rona dhona, he chose to go against the house-mates and stand alone. That shows the man has a mind of his own and does what he believes in and stands by what he thinks is right. That is genuine.
The only "real" guy in this house full of two faced .