I can confirm that the Night Mode mod does not invert the screensaver colors when my H2O is sleeping, or off. The image is displayed the way the image is in the file that's being used.
This is the link to the Night Mode I used:
https://www.mobileread.com/forums/sho...d.php?t=212162 (I used the one for the H2O which is linked to later in the thread).
Not sure how different that is to the Night Mode mod on the forums which gives an image to tap on your Kobo, rather than the workaround in the mod I opted to use. However I can't imagine it's so different that it would affect the screensaver.