Thanks for the useful feedback.
The misunderstanding I had was the following:
If you import a raw file which has a XMP sidecar file, the "before" will have the settings from the XMP file.
If you import a raw file which has no XMP sidecar file, the "before" will have the settings from the original raw file.
Therefore, "before" does not necessarily have the original raw file settings upon import.
You can give "before" the original raw file settings as follows:
Make a snapshot.
Click Reset.
In history, make the "reset" the "before".
In snapshots, click the snapshot you just took to restore the settings.