hi Brian,
I have not tried directly during import, because I want the field "original filename" populated as well. So I do first the import without name change, then select all and rename them. (If building of previews is running at the same time, occasionally there may be a file access conflict and some do not get renamed...so stop the preview building or rename after they are ready.)
Then all date options only refer to the exif data of the image, like you expect.
Cornelia