I remember those Levi's brand 501 jeans used to scratch the back of chairs! Lucky they were leaning against a log.
You are right that "cold" is not in the story--that's why I bracketed it.
Did you notice that four tacks hold down the postcard in the story, but there's only one tack in the movie? What, if anything, do you make of that? I took the four rivets to be at the four corner's of a jean's pocket. Maybe, as Jack is under Ennis skin with the shirts, he was in his pocket with the tacked up postcard.
Speaking of the postcard, when Ennis said to the store keeper, "One's enough" weren't there two layers to his meaning? Whew, one's enough! and One's one and only. "Man cannot wed twice or lose his soul."
All this is making me crazy, I know.