The large banks based there had promised to move out over a Yes vote. So your guess is about right. Scotland would quickly have turned into an unemployed cesspool.
The way I read it was that the major banks would move their headquarters out of Scotland - mainly because the issue of Scottish currency was completely up in the air.
No actual banking jobs in Scotland were really threatened.
The currency issue and what that would do to both economies was the really big unknown issue that swayed folks in the No direction IMHO.