Sorry, I wasn’t clear. There was one version of the BelAire where there was no pillar between the front and back doors. I thought they called that version a hardtop, and the one with the pillar just a four door sedan. But maybe my memory is failing me.
It was a four door hard top. It had a lower roof profile than the boxy sedans.
Then there was the two door hardtop. It was called a "hardtop" because when all the windows were rolled down, and you opened a door, there were no posts or window frames....just like a convertible door.