It doesn't look like one to me. The only thing I see is that the die has been heavily polished. Chris
In that second photo I see what looks to be a repeat of the left vertical displaced to the SE, is that what we are talking about atrox? But it looks incusive.
I was looking through a bag of 40% Kennedy half dollars when I found this. Has I am going through more I am finding a couple more of this D from different dies...so it can’t be an RPM, just a different punch.