It is a RPM, but probably one of the minor ones. I couldn't find a match yet. Coppercoins 1959D-1MM-054 looked close. It had the mark on the tail of the last 9 and location was close. But the die state on CC was later than your coin. Location was close, but slightly different. Nothing matched on Wexler's 111 dies in his book. But it is a keeper. If you get several of these, you might want to submit it to John. (You might send him an image) The image is getting there. The only thing missing is a slight light showing the lower serif. You might rotate the coin 180 degrees to get the light so shine on the lower serif. That might give me a clue what is is going on in the dark. (Please include the full date) I might be able to make a composite image with the two different images.