Scott, with all due respect, I'll add a few things with my copy of
Story to Screenplay in front of me.
As published in
Story to Screenplay, the screenplay dates the confrontation at the lake simply as 1981, with no month attached.
This is a significant difference from Annie Proulx, who in the story clearly places Ennis and Jack's last trip into the mountains in May 1983.
The published screenplay places the scene of Ennis reading the postcard outside the Riverton post office in 1982, again with no month attached to it.
The November mentioned in the text of Ennis's postcard clearly must be the same November they were arguing about at the lake. And this is why I personally pay no never-mind to those dates in the screenplay. I don't think it makes sense for the the two scenes, the confrontation at the lake and Ennis reading the postcard, to have taken place in two different years.
Somewhat allowing the story to inform my understanding of the film here, I take it that in the film the final camping trip and confrontation took place in May 1981. I'm guessing that after Ennis's collapse and before he drove away, they somehow made up and Jack agreed to meet Ennis in November (considering the text of the postcard, maybe Ennis agreed to try--but ultimately failed--to get away in August after all). I take it that Jack dies sometime in the summer of 1981, and Ennis gets his postcard back in, say, maybe October of 1981.
Just my POV.
Almost as an aside I'll also say that I'm not happy that the movie, according to the published screenplay, kills off Jack two years earlier than Annie Proulx did in the story. In the script, Jack speaks about the few times he and Ennis have been together in "nearly twenty years," whereas in the story he says, exactly, "twenty years." In other words, in the story, the final trip into the mountains is a good, round, twenty years, after they met at Joe Aguirre's office in 1963.
