imho, that's what clear coat is good for.... to degrade.
the buggered screws were bothering me so much, i wrote the seller and asked him his thoughts. he felt the same we do, caused by dealer or owner.
In 1969, the service area the owner lived in was somewhat remote. The seller told me he has several pages of service records written in the owner's hand, both on the CB750 and the SuperHawk he traded in, so it's likely the owner did his own servicing and may have had no impact driver. Or the local dealer didn't have the impact driver and buggered the screws. The seller suspicions the owner may have been a tinkerer, he was in sound design, so likely he installed the synchronizer on the bike and may have removed covers to see what what was underneath.
Mid-late 60's, we had an International implement dealer who sold Yamaha's, another Bridgestone's, in our hometown of 1200 people. both implement dealers would sell them, neither would work on them, so we were on our own. we had a local fellow, who did tune ups and repairs out of his garage. our YDS3 had a tooth knocked out of 2nd gear, i remember Dad dropped the shifter pan to diagnose the clicking sound he was hearing.
I'm just saying, the sophisticated designs honda used were not what many rural or semi-rural dealers were used to seeing, much less working on, compared to other brands of the day. service availability or quality in these rural/semi-rural areas may not have been up to par either, compared to larger cities. it's possible some event happened to the bike requiring engine removal, but what the seller knows, based on hand written records of the owner, i would tend to doubt it.