[O.B.Left]

Yup it does appear to be a Rotated turn in that it is more perpendicular to his spine angle here, but Rotated can locate the Turned Shoulder Plane after all, per 10-13-C. So Id say he is Rotated shoulder turn going back then On Plane on the down stroke.

Great question as to whether this is a short iron thing for Hogan, I looked at a driver swing and he still appear Rotated and then On Plane to my eye but Hogan did stand in a very erect posture ,maybe given his height perhaps and so his version of Rotated is still pretty darn Flat.