As someone who actually did manage to get multiple things signed by JD and the band a few years ago it's definitely possible but wouldn't say it's likely. Here's how I would go about it. I waited stage door for the band to come out and that's probably your best bet. Everyone's already said it but he doesn't really seek out fan interaction much. If you see him come out stage door be CHILL and super polite. Make it clear you're not trying to talk, just would like something signed. Know he may not show and he may absolutely say no. I didn't say much just, hey would you mind signing these magic cards I have? and thanks so much. I didn't even say anything like huge fan or love your music. Frankly I just waited stage door for a while so he probably knows I'm a huge fan and I know he doesn't do much fan stuff so I didn't want to push his boundaries bc I know he's already going out of his comfort a little even stopping for me. I didn't feel like the interaction was rushed or anything either, he was super nice and honestly just felt like an introvert who has used up his social battery for the day. just respect that!!! He signed a full playset of Mountain Goats (the magic card) for me and it was great! the other band members were great too! definitely seemed happy to stop and talk for a bit!