NPD almost never comes isolated. It is usually diagnosed with other Cluster B Personality Disorders (especially Histrionic PD and Antisocial PD). A single, clearly delineated personality disorder is exceedingly rare. The norm is double or triple diagnoses from various axes (with Obsessive Compulsive Disorder, for instance).
But a seductive behaviour is not an NPD trait.
Here is what the authoritative “Review of General Psychiatry” has to say:
“HPD must be differentiated from … NPD. These disorders may coexist in some combination with HPD, in which case all relevant diagnoses may be assigned.”
“… (NPDs) have far greater contempt for the sensitivities of others than those with HPD …”