It's the skid toe shoe for Hubert.

MajMike was savvy enough to guess that Sanger knew what he was talking about, but he muffed the location. Nope, not vegetation-dings, either, John. The chipped areas are from gravel 'n' stuff kicked up by the rotorwash in "unimproved" LZs (never did see an "improved" LZ, except the hot ones that got worked over by suppressive fires) and the abrasions (red circle) are from contact with the towbar during ground-handling. The towbar attaching ring is on the inside of the skid, just aft of the skid shoe and the bar angles up when it's hooked to a tug; hence, the abraded area is always on the side facing toward the fuselage. In this case, the fuselage was to the right, so the toe shoe was on the left. Elementary, my dear Mikey.

A little tip-toe on the skid-toe, eh, AFSis? Makes getting in-and-out of a Huey a whole bunch easier than a Cobra...