at his fittest - which is now for Brothers - his body is as below.
and no it isn't a pic of him from his early modeling days. back then Siddharth Malhotra was also a lot more awkward and not as six-pack'd. eg this pic below.
btw check out this link to archive of young Siddharth Malhotra from his early modeling days. he was such a cutie from the get-go.