Your best bet is to PM the owners in the threads you found in your search. Here's one thread Forest River HTT Bunkend Field Fix Kit
As I recall, the new seals were effective. Few members on the forum today can answer your question directly about the seal kit that FR was sending out, although I believe Bikendan had that kit installed. Shoot him a PM.
As for replacing the bunk, there are a few who have done it. I'd have to search and find those threads, though, but I'm on an iPad and it's a bit limited at the moment.