There is a similar idiom in English, but it doesn't mean quite the same. If you've got 'a feather in your cap' you've done something good/praiseworthy/laudable....: 'He just needs another 2 customers to take him up to 1,000 - that'll be a real feather in his cap'.
But I can't think of an idiiom that refers to a mark that qualifies you for special treatment. In your case we'd just ask 'What's special about him?' or 'Why does he think he's [so] special?' People who are privileged just because of a rich background are said to have been 'born with a silver spoon in his/her mouth'. And occasionally - not common or idiomatic - I've heard questions like 'Does he know a secret handshake?' - a reference to Freemasonry - Wikipedia, the free encyclopedia .