If I already have a 1912 10 cent coin, do I need to have this coin in my collection if I don't collect coins by variety ? Only by year and mint
It sounds like you have a coin in a slab that is mis-labeled. You say you are collecting by date and mint and you already have a 1912. If you don't have a 1912 D then yes you can use theis coin (what the label says doesn't matter the COIN is still a 12 D) If you do have a 12 D already then no you don't need it.