If it was an IgG test, it is about 95% accurate after 12-16 weeks for HSV2.
For HSV1, the IgG test is not as accurate, missing up to 30% of infections. So you can be 95% confident you do not have HSV2 but only about 70-75% confident you don’t have HSV1.
The most accurate test for both is the hsv Western Blot, only conducted at the University of Washington, though you can have the test done through your doctor.