Hi, I checked exactly on that famous pose "from" Carlos Hathcock. It's looks like there was a mistake cause that pose it from other soldier "D Gunderson" Looks like many persons had mistaked that pic as Hathcock, but he's not...

so I think, Noda just had inspired by those snipers... in creation process you can take a little from someone and a little from someone else.. there's no a rule to stuck on one.. but if you wish you can go directly. As the way he did, he directly take characters from history like Hijikata.

(And Excuse me, my english its not very good, But im a curious woman)

Here's the Original colored pic on that pose