It is very possible the mint mark was added at a later date. With the most popular coins counterfeits do exist. I have seen some where the mint mark was cut from a coin then attached to another to make it more valuable. In that type of counterfeiting you wanna look for heat marks, discoloration around the mint mark, also (like this coin, but not saying it isn't legit) a buildup of grime around the mint mark. It could be leftover flux from the weld.


















