Note the direction. It is die wear. The mintmark is not enlarged, the area you are looking at is not a mintmark, but a die wear issue in that direction. If it were a RPM, it would be raised, just the the mintmark that is there. No evidence of a separate mintmark punch direction. Not a RPM. http://varietyvista.com/05%20JN%20R...%201964D.htm Note how the RPMs are a separate punch, enlarged and not in the die wear zone that are raised?