I've heard it once said that the rule of thumb is that the damage you see is 10% of what's really there. After repairing leaks and delam on a 5er of my own I can attest to that.
If they can prove to you with pictures the rotted stuff was replaced (and I assure you there is rot in there) and you can verify for yourself it was resealed and it passes a pressurized leak test only then would I consider, and only after working them down seriously on price.
If it was the floorplan I really wanted with the options I really wanted then I'd think about it after verifying all of the above. But there are so many more units out there.
I had to sell mine below market value to get it to move. I was clear with the sales ad and had pictures to prove the repair, and evidence to show it was done better than factory. I must have done something right because it sold quick, but I knew not to go into la la land and think that my trailer deserved full market price.
Now I shop with a rubber mallet to test the walls / ceiling / floor inside and out :)