Yes! After you login to your account, you can view all previously purchased restaurant certificates. You can filter your certificates by unused, used and all. If you do not see this option please make sure you have the most updated version of the app downloaded.
Restaurant.com also has a mobile site that looks and functions similar to the Restaurant.com Mobile App. The mobile site will allow you to view all of your purchases, both unused and used. You may also present the restaurant certificate to your server from your smartphone.