I applied to MSU. If you did not do a rotation there, you may be out of luck. I just finished a rotation there and they told me that they tend to only rank students that have done rotations there. They will only interview students who are applying through the osteopathic side this year (as they have the last two years). If you apply through the allopathic side they probably won't even look at you. They say it's because they're happy with the D.O.'s that they get through the osteopathic match and because they don't have a linked transitional year for the allopathic applicants. Hope this helps. If you're really interested though, try e-mailing the program directors (Dr. Andary (allopathic) and Dr. Wieting (osteopathic). Good luck!
If you rotated at MSU then you don't need to interview there. They will call you if they have questions for you (and you are more than welcome to call the program directors if you have questions about the program). Otherwise your rotation was your interview. Good luck!