This one is very interesting. It is a late usage R1c on very thin translucent paper (which one would more frequently encounter on early printings not late printings) with a vertical mesh ala laid paper (see previous debates as to whether said laid paper exists on 1st issue revenues). Additionally, the surface of the back has odd impressions of circles and squiggles, almost like what you would see if someone doodled on the back with a pen without ink. I’ve seen this surface texture anomaly before on very rare occasions. I’m not sure what causes it.
Below this image is a link to a very high-resolution image of the back.
What’s going on?