1953 D/D

Interesting mark to the West. There is one RPM with a similar location of the mint mark, but I don't see the inside mark inside the mint mark. Here is an image of the RPM in question.

The mint mark looks much weaker than the one from this die. Maybe a few more rotated images you could see the inside loop? What can make the mark you see is a fading die scratch, making it appear as a RPM. But, the inside loop would be visible if it were a RPM. So take a look and see if rotating it in the light at different angles shows anything the camera didn't catch. If not it could be a fading die scratch. Keep us posted.

I'm betting it's a RPM in a late die state.

If it was Mechanical Doubling, then the number right above it should show some doubling.

The location was very close to this one, that is why I mentioned it. the West line appears to be something, but in the image I posted, the serifs are a lot stronger, which means the corners of the D on the left hand sign are curved. I don't see that on the first image, just a straight line in the images that I've seen so far. The images is now getting glare where you need to see. Keep looking and shooting till you can get what you are seeing. Finding the coin is just one part of the game. Matching it to a known die can be harder or in some cases impossible if it is very minor. So I would still say the jury is out yet on this one.

I was noticing on the last two images you posted, the light appears on the first one as coming from 12:00 on the image with a secondary light at 6:00. It is not necessary to have two light sources except in certain situations. On the second image the light is one directional and coming from 6:00 direction. that better. Now try light from 9:00 and 3:00 to see of the inside loop lines appears on your images. You don't need to move the light, just rotate the coin to make the lighting appear from those directions. If you have a secondary unwanted light, you might wish to use a tissue over that side of the scope to block the light. The way to tell from which direction the light is coming in is to put your hand around you coin and see which direction the unwanted light source is from. Tape a facial tissue on the side of the scope and remove the unwanted secondary source. see if you can see the West inside loop. Then you might know for sure it is a RPM.

Also: crop your image and rotate it to the normal position with the date square to the world. Everyone get used to see it that way and it help to have a better perspective that way.