Cliff - welcome to the new AC club
When I removed the rear TV, I noticed the manufacture date preceded the coach by about 18 months.
It might be a bit of a stretch to link the date of manufacture with corrosion. If Winnie had it in production inventory for two years, it would have been stored inside their monster warehouse.
I can't imagine RVP building it and letting it sit around two years - if they are the culprit, then their manufacturing scheduling is a little wonky.
We like to sit and wait on repairs - a little more hassle up front, but it solves problems of dealers sitting on it.