@Colinf1: yes.
These are pictures from inside my car (caution, rust showing in hidden corners...)
And after, once repaired:
But I'm not able to say if the door step and B-post inner closing panel are welded together on this corner, I did not see spot welds here.
I know that the 3/4 panel is not welded to these parts, besides the two spot welds close to the fold (see first picture) and at the outside there is some factory brazing on the lower lip where the 3/4 covers the door step.