Technically the Pluto-Charon system is not a primary with a satellite, but a double system. The center of mass of the system is not within either body, but in the space between them.
As I love to point out, the problem with this definition is that it also applies to the Sun-Jupiter system.
This is true and will remain true for another billion and a half years at which point the Sun will have expanded enough to put the barycenter under the surface of the photosphere. The barycentric point (as it is known) if at 1.068 solar radii.
The location of the barycentric point is of some interest, but isn't really very meaningful in defining the properties of two body systems.