It's tricky. Some people get hit in multiple places, some don't. We aren't sure why this happens, but there are ideas (Immune system status, length of time you've had it, etc)
My husband had oral herpes, about a year into the relationship I found out I have genital, and we never used any precautions other than abstaining during an outbreak. To this day (18 yrs later) we've never had an outbreak in the opposite area. And he was a horrible nail/cuticle biter, if anyone would get whitlow you would think he would have it.
But then you get people that get it in every location possible. There really is no one answer for that question, sorry.
The swabbing on her would be pointless if she didn't have anything to swab. The blood test (assuming shes had it awhile) would be the best bet. Was it an IgG type specific blood test?
And with herpes you can carry it and never know. Although she had an ex with cold sores, there is a possibility that she may be negative. Just wanted you to keep that in mind.