They scan them and then print them on finger print cards. ATF took them with not issues. They charge but it is a small fee, plus they will print extras if you want.
That's not too terribly bad at all. I know that the SilencerShop kiosks do them as well if I'm not mistaken. I've only used the kiosks for a recent Suppressor purchase. Looking to SBR one of my guns soon.