This is a passer. There are 4 known mintmark positions on a genuine, and this does not appear to be one of them. There was only 1 punch used, so shape should be there EVERY time. It is very difficult to authenticate coins with pictures, and the SVDB is not a rarity by any means, it is better to move along on anything questionable, more will follow. Remember, even if genuine, it appears to be a problem coin. " There is no price to cheap for a problem coin " Rick Snow. He says that for a reason.
I agree with Jack. The mintmark looks questionable (especially location and dark area around MM). I would pass.
Imaginative Opinion OK, adding a mint mark to a toned coin would be readily apparent. So the person who cleaned this Cent did it so the mint mark could be added with the idea that subsequent re-toning would cover up the work. But then he doesn't do the re-toning? Maybe he saw the mint mark was out of position and simply gave up on this on to move on the the next. Plausible?
