At the service panel it is bonded by virtue of the main bonding jumper. I do not feel additional bonding at the service panel end is needed.
As long as the EMT is continuous from the bond on the ground rod end all the way to the EMT connector that is tightly secured in the knockout of the steel (ferrous metal) of the service panel,
then the bond at the service panel is already in place where the GEC is tied to the panel steel enclosure by the Main Bonding Jumper (MBJ).
The key, to the bonding both ends requirement in 250.64 is that the ferrous raceway and enclosure is electrically continuous through tight EMT fittings. Look at that second sentence in 250.64.
The physics involved causes a current to flow in the steel, when the current is flowing in the GEC. To maintain the efficiency of the physically protected GEC the current has to travel on BOTH the wire and the pipe. The MBJ to panel enclosure to EMT connector to EMT path is the service panel end bond.
Now, if the EMT used for physical protection of the GEC is just a short segment on the outside of the building, then the EMT segment (that is not electrically continuous to the MBJ) has to be bonded at both ends to the GEC wire. Then the wire and the EMT segment can share carrying the current.