Very likely, someone at the mint filed the coins down to improve their look, but they were a little too overzealous and created either a weak "D" mint mark or coins with no mint mark at all. Bottom ...
Expert @CoinCollectingWizard recently highlighted the coin collectors should be hunting for, noting that only if it has the unique feature of a tiny mint mark does its value dramatically increase.
Following the sudden passing of their brother, three sisters could be set to pocket their share of a huge cash windfall after discovering the value of the coin he left behind ...