Can't you just take the MPEM into the dealer? I mean if it is inconvenient for taking the sled in.
If there was no paperwork on the sled, you need to pursue that. I am not saying anything here, but if the sled does not have a clean record, and you take it in to get it reprogrammed... dunno what might happen. I would be tempted to call the VIN number in to law enforcement and check to make sure it is clean, if it is you can apply for a lost title or abandoned vehicle title, the law enf. should be able to tell you the last registered owner, go get a notarized bill of sale from them or whatever your state requires and get your paperwork.
WAIT - this thread is old old old, who dredged it up?