Sure thing, Sir.
Yes, those are the choices, but only for 1/2 of the GUI. With this particular edit only the choices for this tool will be affected.
Part of what makes FC unique is the separation between the GUI side and the command line side. For this reason if one wishes to address a property list, like obj.cutMode, accross all GUI interfaces, the property list must be edited on the general GUI side, which is Qt based, and in the python side where you have made your edit.
The good news is your edit should be visible and usable, but only in the Data tab -> Properties View for Cut Mode. It will not be visible in the window editor for the tool - that is the Qt side of the GUI, and is not python based, except for the interfacing with the command line side.
I don't have FC in front of me, but look in the property list in the Data tab for the Cut Mode property. Your updated selection labels should be in effect there, but not in the window editor available upon initial clicking of the 3D Surface tool icon. Also, you should know, based on your description of the edit, you will likely have to delete your current 3D Surface path and recreate it with your updated PathSurface script now in place.
Hope I addressed your issue. Unfortunately my ability to provide more details and exact FC terminology and references is hindered without FC in front of me. I'm on an Android device.
Glad you're tinkering.