The wear on the 9 and 2 in the date looks to be damage from an average coin counting machine at the bank.
The date is on the master die. The individual digits are not hand punched. Only 19th Century coins from the U.S. digits were hand punched. The 20th Century coins the hubs transferred the obverse devices to the dies. In this case a 1941 hub and a 1942 hub were miss takenly used to over date this die. Thus making an over date die and striking over dated coins. The mark looks like a gouge and the die flow lines near the date makes it appear to be something that the mind picks up on. If it were an extra one all the other devices would be present making this coin look double struck. On letter isn't possible to be raised from the die.
Your looking to close again and spending time on stuff that Your looking to close again and spending time on stuff that will not pan out. Please heed the advice on here and move on - don't worry sooner of later you will find them.
Though I think it's an ordinary dime , your pictures using a 10X loupe for enlarging are great , good job . rzage