Ausiello has since spoiled that all three of Rory's boyfriends will be appearing. I'm not sure that they really need Dean there tbh as he was Rory's boyfriend when she was only 16! But Dean did have a pretty depressing ending, so I suppose that will be nice to get closure there at least, but yeah my best guess is that it will be more of a cameo. It feels to me like Logan and Jess are the boyfriends who had the bigger impact on Rory's love life