Whe we bought our Virgo Voyager we bought it with osmosis and had it treated. That was about 15 years ago I suppose. We were told then by our surveyor that all fibreglass boats will get osmosis, it is just a question of when.
I think that when buying a boat the age of a trapper you have to be prepared that osmosis may well feature in your life. Osmosis has never actually sunk a boat yet, and quite possibly never will. It's more a cosmetic thing but it does put buyers off, not a problem if you intend to keep it.
Sadly for me, Securus is going, osmosis or not. She will probably end up being treated and then put straight back on the market. Anyone who felt they couldn't afford a 501, this is the time to get a bargain.
When she has got her 5 year hull guarantee we will put the price back up.