There seems to be no rhyme or reason as to why decals peel. Mine spends the vast majority of its time in covered storage. Decals peeled after 6 yrs. Others have had decals peel after 2-3 yrs. And another Montana just like mine except 2008 model in same storage decals still look new. And it is not just Montana. Decals peeling is a problem among other brands including some motor homes. That is not a sign of roof problems.
As far as the pictures, there are a lot of shadows of different shades in many of the pics on floors and cabinets. Hard to tell much about them. You might question the salesman and ask for better pics of the area.
