Can promo codes be scanned in the mac app store like gift cards?

I'm hosting a booth at a few conferences this summer with demos of my mac app. I'd like to offer a small number of promo codes to people who visit the booth, fill out an application and meet some requirements that I think make them shoe-ins for being influencers, maybe 3 per conference.
I'd announce it kind of like a contest, but the idea is they are people who are very interested and would promote the use of my app.

I'd like to offer them something substantial to take with them that has the promo code on it, kind of like a gift card, so they don't forget "this is valuable". My first thought was actually give them a gift card, but that's silly because the whole point is no real money needs to get involved, and a real gift card could be used for things other them the in-app purchases in my app. Getting custom-printed plastic cards is the easy part. The hard part is what I put on it.

Is there a way to display promo codes so that the gift card code scanner in the mac app store can read the promo code? Is all I have to do position the human-readable code in a mono spaced font in a box along the top edge like a gift card and it'll be recognized? Do we know what font the gift cards use? / Does it matter?