I do believe the first year of GD was 2012 my buddy bought the 101st Solitude of the line as far as construction they are pretty much built like any other 5er the French brothers who started GD came from Keystone so that tells ya a lot the Apple did not fall far from the tree so when looking at any used 5er you are looking for water incursion all appliances working etc.. etc.. lots of videos on You Tube on what to look for I would also look at the roof as GB did(or still does use wood for their roof trusses instead of aluminum