I think that is actually a 50 milion note - but anyway -
I too have a german note that has an asterisk, but it is in the front, well, between the alpha character and the numerals. I have often wondered what that is, and comparrison to other notes revealed that it was not the norm.
I say they were likely replacements, but it would take someone with a more thorough knowledge of these particular notes to say. If they are replacements, I think that it is just plain odd that they'd find it necessary to go to the trouble for them... especially the uniface ones which, as I understand it, were simply not worth wasting the time, effort, ink and money to print on both sides.