"On the Executive, you could optionally have removable type-bars. "
Yup. This feature allowed IBM to offer the Executive in various languages, and in special versions for specialized fields.
If I remember correctly, all the type bars on the Executive could be exchanged for others, which made the machine very flexible. IBM was very good at that sort of thing.
I do know that the one I used had characters for superscript "th" and "st" It probably also had "rd" and "nd". I suspect that was a fairly common option, since it would help documents have that typeset look.
The Executive was a pretty common unit, particularly in legal offices, small publications, etc. My hometown church had one for the secretary. She used it to create the bulletins.