71 slant 6 - air filter mount

I can tell it is a carter carb, but is it a 1bbl or 2bbl? What does the old one look like? The picture of just the filter mount, or the one on the carb, in Professor Fate's pictures?
The pic of the carb is a 2bbl, it's the only one I could find with the wire bail. Either one could work in a pinch.