I was just wiki-walking around my country's (Netherlands) history when I stumbled upon this topic:
She is the wife of the god Freyr, whom apparently the Frisians and the Frisiavones were a cultus worshipping him.
Now I looked at the gullgubber of that page and the texts of this image on the Gerdur page says the two figures (representing Freyr and Gerdur according to the Dutch page of Gerdur) have a "leafy bough" between them. But perhaps it's just my dirty mind but I immediately thought "That's no leafy bough! That's a ... and it's not between two people but between a pair of ..."
I just want confirmation from a historian to see if I'm the first one to notice this and whether or not this was indeed the artists intention ;-).