It looks like machine damage on th3 "S" mint mark. Note how they reduce the size of the devices. Hub doubling enlarges the devices. Not sure what you are showing on the last image. If that is the bow tie, then it would be too minor to be listed. The first image looks like MD as well. But a side by side of a normal coin's devices and your coin might give us a better idea for size of the devices between the two.