Yes, and that’s how most shows do it. Print the personalized cards for everyone pre-registered the day before or once online registration closes. Then print a stack of blank cards: same show name, same voting QR code, a big empty box for the number. As a walk-up parks, write the number on a blank with a marker. Nothing has to be printed on site.
FAQs: Show day: check-in, windshield cards, and the gate