Well they tried this again to fix the issue in the 1960's that also looks like an engraving on that area, but not examples were affected.



Also on the other coins from the 1950's era, they enhanced the hair line:

So alterations were done some where in the process. If they had enhanced the master hub, all would have looked that way. If they had enhanced the master dies for that year, then 50% could have been enhanced. But it looks more like an alteration on the Working hub or a working die, as not all are affected, just a few here and there. It might a the polishing stage, they noticed the weakness they polished out, and they added it back in again. Which would affect just that dies coins from that point forward. This happen on the 1953 proof
DDO die on the jacket:

Which is listed, but only part of the run would be affected. (Just the later die states)
Edited by coop
10/15/2021 1:19 pm