Should I trust this guy or is he a fraud?

I recently advertised a baseball jersey on Craig's List for $120 and recently received a check for $2550.92 from this guy who sent a check from Tabor Academy in Marion MA. I will add details/emails he sent me and let those who choose to answer be the judge as to if this guy is legit or if he is a scam artist...I need some help, so I am looking for people who are serious in letting me know. Thank you ahead of time...