Sorry, the 'best by' date was meant as humor - the vinyl gets faded and chalky with time (a long time, usually), and also starts popping out on the corners as it gets hard. On the newer Bigfoots, they put a screw through the vinyl trim at the ends to keep it there. Another thing that shrinks is the window insert molding. I replaced it on my last Bigfoot camper, trying my best to compress it in length as I knew it would shrink - and within a year it was 1/2" back on both ends.
Older Bigfoots (my '86 5th wheel and '98 camper) both had cad plated sheet metal screws in the joint. In places these got rusted enough to hardly even be there anymore. Other places just fine - it must depend on where the water collects. Both were kept outside. If I were to remove them I would replace with SS - a box of screws from McMaster is pretty cheap (don't buy those at the boat store, their markup on stuff like that is enormous!). My new Bigfoot ('08') has SS hardware at that joint and pretty much on everything else, a nice change.
They still smeared silicone on the outside of every joint though. For removing it I tried several commercial products and found
this product worked the best. You peel and scrape off all you can then apply this to the nasty film that is left, works pretty good, takes a 1/2 hour or so. The insidious thing about silicone is that it sticks really well some places and not at all others - doesn't seal, and doesn't come off either!