Getting a new medical here is the way to go. Somebody screwed up with your packet and your medical was left out or lost at entry. I think it was left out and that medical you have is the one that should have been in the sealed envelope. We do not get a copy of the medical, you will get a copy of the vaccines and just the vaccines. If you have the actual medical someone dropped the ball. Since your RFE is asking for proof the medical was conducted before US entry send in the one you have plus the new medical. This way you can show you did have it prior to entry.