Near the end (as of 1.37), there's this passage:

I marvel at the odds. That my life could turn around entirely in such a short amount of time.

Countless cups of coffee and gas station snack packs. Four boxes of gold. Five states. Three weeks of dusty, desert roads. That’s what it took to get us here.

But either I missed something (the most likely possibility), or there's a bug that skipped a section, or that's an editing error, since I only count three boxes:
1. Shiprock
2. Chip off the Old Block
3. Valley of Fire

I see "four boxes" was changed to "three boxes" in the remastered version, so that answers that!

Looks like there are still a few references to that fourth box, though.  When they find the treasure at Arches,

Without being asked, Marina retrieves the screwdriver and hammer that I’ve been using to smash the locks. She sets them down in front of me, but I offer them to her.

But the Shiprock treasure wasn't locked.  Was it originally written that they find treasure at Canyon de Chelly?  This seems like a reference to a dig there:

Pangs of guilt remind me yet again of the broken brick at Canyon de Chelly, and I make my umpteenth resolution to be more careful.