I am sure others will chime in and I'm no Miyata expert. I will say that touring bikes are sought after ,so the 610 might have more value.
but couple hundreds bucks each I'm guessing...PS any rust or dents would be less. PS. I picked up a rather minty , original Schwinn Voyageur , made in Japan , Columbus tubed , for $350 recently . It almost looks unused . I don't know if it is a comparison to the Miyata 610 . Remember this is only an opinion, you know what they say about opinions...