I'd give them a few extra days to blow the sand out of it. (Insert sillly smiley face here).
No. I think the sand will stay.
This is how Phase is implementing 'film grain' looks.
Death Valley sand is pretty coarse and will be a good representation for Kodachrome 200
Next month the team is heading to the fine gypsum sands of White sands National Monument to input their Velvia grain profiles