If this route is selling DPS, the ship you’re on will have updated seat covers in D1 and a few extra bells and whistles. It will feel fresher and the seats and IFE should work a bit better as they were “cleaned up” in the most recent mod.
Best way to tell this is if the section immediately behind D1 is 2x2x2.
If there’s no DPS on this route, expect a tired and pretty shabby old product.