No Problem
I have same thing, got approved when in india, when I came back did stamping. everything is ok.
But if your mail are not on hold then you should have someone to pickup mails. so your approval would not sent back.
I ask my attorney, for this also he was going to send me approval notice to india and and can show at airport so may be you can do stamping at airport.
But for my case attorney got approval notice 5 days prior to my return date.
