I believe they get the pink RV antifreeze prior to leaving the factory, so that's not a sign of weathering.
Rockwood changed fabrics about the time our 2015 was built last September, and also updated the exterior graphics
They lightened up the brown on the front cap quite a bit on the newer 2015 Diamond package models. That may have been because some dented easier in the sun due to the dark color.
Really just comes down to how much you like it, and how much they want to sell. I'd want a great deal on a unit the dealer has had that long.
If you buy, consider better in tires in load range D or E quickly. The LR-C tires FR installs don't have much reserve capacity, and won't improve with age.
2017 Open Range - Light 297RLS, BX1 Gooseneck
1997 Dodge Ram 2500 CTD LB 4x4