Have you ever placed the Pazuzu sigil over the picture on the image of the Pazuzu statue?
Try and you will see that the sigil is based on its shape and marks out its head, wings, arm, legs and feet. I would say this sigil is a sigilic drawing of the Pazuzu statue. The Humwawa sigil is also based on the traditional face of Humbaba.
For about 15 years ago when I first became intersted in the Necronomicon of Simon I had a big framed picture of pazuzu with the sigil traced over the glas of the frame.