Upvote:2
Generally it's advised to carry these items in carry-on, so that they can be inspected, which is why Export Certificates are issued post check-in at immigration.
Of course, as you mention, you might want to check this luggage item, which makes it tricky to present.
In this case, your best bet is to contact the airport and ask them for their Export Certificate, and submit it well in advance of the flight, and ask for where the goods can be inspected at the airport, given that you're checking in the luggage.
For example, Bangalore airport has instructions for this, with the Export Certificate form that you fill out, an email to send it to, and phone numbers which you can contact about the process.