Well, everybody else has an opinion here, so I may as well voice mine too.
Fading and wear: These a/c were the F-117's of their day, and I seriously doubt that they were left out in the open more than was absolutely necessary. That is what all of those nice canvas hangars were for. Sure, you see pics of a/c with wing replacements (DH-2's come readily to mind), but I venture that those are due more to battle damage, ground-loops, and the like than they are for fabric that is worn and faded.
Cleanliness: These a/c, when coated with castor oil, attract dirt and grime worse than my boy. (Here's an experiment you can perform at home: On a July day mow the lawn, then take a boy between the ages of three and ten, give him a popsicle, tell him to eat the popsicle and run around the yard for 15-30 min and make airplane noises. Observe results.) (Note: I have done this and can supply data.
Now as Neil pointed out, there are a lot of men around these aerodromes whose sole purpose in life is to maintain these wondrous machines. Are they Mabel the house maid? No, but you can bet their Sgt. is keeping a keen eye on their efforts. IIRC, a friend told me about the interview with Voss' mechanic (Timm?). I believe C&C published it a long time ago. His clearest memory of Voss' Tripe? Spending the better part of everyday scraping the castor oil gunk off of it!
Used? Yes. Abused? No. However, if you want both, build IRAS a/c, or those from the RCW. They are horrid looking. Will you win the big contest if you do a lot of weathering? Probably not. If winning the contest is your goal, then my advice is to build Bf-1-oh-things.
It's only a model.