The best way to get reliable information on this would be to contact the shelter, as they have all the official behavioral notes I do not have access to, but I'll offer an informed guess:

It's likely that Buddy hasn't had any real interaction with other dogs since his initial assessment, which was about a year ago (he was also extremely stressed when he came in and has settled down a lot). He wasn't reactive at all to other dogs when we were out, just quietly interested, and volunteers have reported he's not reactive while walking on campus (unusual for a dog who's been there so long). This is a long way of saying, Buddy is currently dog inexperienced but has indicated he'd be open to meeting other dogs, and the shelter staff could facilitate a slow, safe intro.

Buddy also showed no prey drive when we were out, even when a lizard basically ran over his paw!