If you've had cold sores since childhood, you have oral HSV1.
An IgG test is the best way to determine this.
An IgG test cannot confirm location.
The general e rule would be if you cannot recall a genital outbreak, then a HSV1 diagnosis will be oral. You will have no knowledge of a HSV1 infection from your youth, but you would almost certainly remember the time if you were infected genitally with HSV1.