Just a normal coin. These initials take a beating in circulation and sometimes they are over polished on the die to remove clashes and get weakened. Later polishings will weaken even more and sometimes they are polished off the die. (So on later examples of that die state, they may never appear again) These were not porgotten to be punched in on the die as all the devices are on the hub. Just polished off later. When this happens the dies go through events. Some collect them, but to me they are just old die examples.