They are different, and also both are documented as supported by Part_SectionCut. As I already noted, I don't know how the fasteners are modelled, and I don't know to what extent either of Part or Part Design workbenches are associated with fasteners.
In my document I used Sheetmetal WB in an included part, which I expected but didn't know to be compatible, and in fact it works fine when the fasteners aren't there but the Sheetmetal BaseBend parts are.
My purpose in starting this thread was to determine where the bug or bugs are so that I can submit a proper bug report, since bug reports not referencing a forum thread are thrown out. This means I'm looking for FreeCAD developers to let me know what bug or bugs are evident here based on the intent of Part_SectionCut. I don't have a personal need for this to work, I'm just trying to contribute one or more useful bug reports as a result of my experiment.