The short answer: Yes, you can see which yearbook photo is selected for each access code.
The slightly longer answer: Since the system defaults the yearbook selection to the first image following the QR Card, you can only be sure a customer made the selection themself if the index image is not the first (default) image.
We recommend including a message like the following in communication profile emails or in a manual newsletter: "Please select your yearbook photo by the deadline. If no selection has been made by this time, we will use the first image as the yearbook photo."
In your Photo Job's Settings panel, you can click on the Manage Names button to see all of the yearbook photo selections at a glance, but to see if a different image was selected, you'll need to look in the albums in your Photo Management panel.
From the below image, we can see that the first child has made a different selection. The second child, however, could be the system default, or it could be the customer's choice.
Both images will still be included in the export.