Oh my goodness, it sat in the vinegar and the peroxide a lil long, but I think I have a 1918/17 Buffalo nickel and it seems like there's a D on back, But I'm afraid to touch it anymore.... it's in bad shape... I've used a magnifying jeweler's loupe hat, magnifying glass, LED lights, etc, and it seems like it...
I'm sorry, I don't have the means until tomorrow, but even then, I don't know if my camera can get it... I need something special.... remember the front is very acid eaten so a lot of stuff would be hard to see.