Any Will Call window can help you! Are you sure they said you didn’t have to register? I would try again, better to be safe then sorry.
I did it for my DD back in January, we are passholders. She received a gift card equal to a one day/one park ticket (it was around $68) The gift card is different then the park ticket, it expires 1 year from the date of issue (verify this when you receive it) and it can be used in any of the gift shops on property.
My DD had a BLAST shopping for everyone! Enjoy your trip!