I found that yachtworld ad.... the boat in Everett WA?
It looks very much to me like what was built in BC as a Windward 850, by Spencer, I believe. Perhaps it was stretched to 30' with a reverse transom.
I agree that odds are it was purchased as a hull and deck and owner finished (could be good, could be bad, survey and eyes wide open). They were a roomy boat that sold relatively well locally for a while.
Have a look and compare:
Sailboats: 28' Windward 28 Sloop - Listing #: 3325