Perhaps more than neck adjustment, it may be that the wear is related to the pickups being raised to get them close to the strings for a bit more dirtier tone. The neck pickup appears to be angled so that the trailing edge, where most of the wear is, is higher than the leading edge. The bridge pickup seems more level; and if he was picking anywhere but right over the bridge pickup, then the leading edge would get the wear. I don't think he was flailing away because the wood around the pickups looks great; just that the pickups are close to the strings. It's a pre-77, single truss rod, so it could be that the same guy has been picking above those pickups for a long time. As for the humx, I don't know. Maybe he was anchoring his little finger there while picking and thirty years of sweat slowly wore it away.
Pete; I haven't seen the listing, but other than comments about the appearance of the pickups in close-up pictures, I don't know that anything has been said that would otherwise be disconcerting about the bass.