I think there is a chain in that drawer. May be his parents akhri nishani and with this in future he will be able to find who his real parents are/were
Since Rudra brought him home and he would have seen that chain with Arjun that means he also does not know who Arjun's real parents are(They are not known to Rudra)
But this identity track i think will not be revealed so soon. It may take a very long time to get to that track. I have a feeling he is from a police family(seeing his bravery). Hope he is not related to Ahluwaliah's.
I do not know why i find the Alhuwaliah's a bit too unnatural or too sweet. No family issues at all, no sibling rivarly, no nokh jhok. Singhania family looks more natural they fight, are sometimes jealous of each other, sometimes forget all difference and celebrate just like a typical family. I like Singhania family especially Rashi, Romit, Dadi and Arjun. I even like Rudra, Kumud and Michael although they are bad and negative towards Arjun. I dislike that Jignesh because he wrongly advises Michael and tries to bring rift between him and Arjun always.
I have seen a few families where one kid get much more attention and others are neglected. Its the same happening to Arjun and the fact that he was adopted makes it more obivious that there is resentment in family to accept him whole heartedly. I personally feel it should be opposite and that a adopted kid must be shown more love since they come with many emotional scars and they feel terribly insecure. We must never make them feel that they are indebted to the family and always remind them that they are part of family. I think Arjun's family is not doing this enough except for Rashi, Romit and Dadi who have whole heartedly accepted Arjun as their own.
I think if Arjun had not known he was adopted he could have tried and demanded that love and attention from his parents but since he knows he is adopted he does not demand it. And i think Kumud is indifferent to rashi too because she once told Arjun that if you were not there i would have left this house long back.
Rudra has accepted him somewhat but not whole heartedly but one thing i like about him is he always praises Arjun whenever he completes a job. But he must not do that in front of other siblings especially Michael who resents him because it will create enemity between Michael and Arjun(sibling rivarly). And even if he praises Arjun in front of everyone he must do the same to michael, romit and rashi which he has never done. Kumud is indifferent to all her children except Michael.