I also noticed that there are a number of scenes where Jack is wearing a "taupe" colored hat vesrus his signature black hat. I'm unsure if there is a trend there .... can anyone enlighten me?
The reunion, the post-divorce scene, and the camping trip after the Thanksgiving scenes.
The three times that Jack mentions living together (even indirectly) with any smidgeon of hope that it's possible.
(Jack also wears a white (?) hat when he's demonstrating in the tractors in the "didn't that pissant used to ride bulls?" scene.)
Another thing I noticed... in the Angry Tussle, Jack knocks Ennis's hat off, but Jack's hat stays on until after the punch.
As for the rings... I think it is intentional that they're shown. They're kind of a subtle reminder of how complicated the relationship is, even when the guys seem to forget it (like during the reunion kiss, during which both rings show up on hands holding faces, or during the Motel Siesta scene, where they're naked except for their rings). Alma's wedding ring also is really obvious in a couple scenes, like right after Ennis takes off on his first fishing trip, when Alma is hugging Alma Jr.
So now that makes me wonder. When we see Alma hanging out the laundry, she's just been washing the shirt Ennis was wearing when he had sex for the first time. But do we ever seen Lureen handling anything of Jack's that would have similar significance? When Lureen knocks Jack's hat off in the car, maybe?