I flew the route last week in Business (specifically paid coach and using a GUC) and received an invite to the lounge.
I was largely expecting domestic F service and was pleasantly surprised with D1 Pillows, duvets, and amenity kits. They also had D1 alcohol kits. There is a single meal service which is breakfast (in both directions) which is about 2 hours before landing eastbound and right away westbound. The one thing that was definitely not D1 was the domestic first class seat.