Photocopy only or Certified

Hi,

I am going to ask my medical school to send Form 186 with other documents to ECFMG. It was stated that the med school should send two copies of my final medical diplomas. Is it a photocopy only (without any stamp, just like when out of the photocopy machine) or a certified one (means my medical school has stamped on it to state that it is an original copy)?

All my forms will be sent directly from my medical school in one envelope as I am sending Form 186 which is signed by my medical school official.

Thanks.