This is a strong single action grip. Though the left thumb is toward the top of the shaft which is indicative of a weak single action grip, the #2 pressure point is on plane which will support impact and therefore qualifies as a strong single action after all is said and done. The #3 pressure point looks in good position on the aft side of the shaft but the right wrist apears to be a bit low. This might be due to the reduced #3 accumulator angle.
This doesn’t seem to be the kind of grip that results from taking the grip at impact fix location and getting the wedges set.
I could be completely wrong.
Furthermore, where in the book does HK use the term "neutral" grip?