I can't answer your question about the different markings. I can tell you that my USPc with KI date code (1998) is marked "Heckler & Koch GmbH" with "Made in Germany" beneath it, same as yours. My guess would be the markings were variable depending on the production year.
Perhaps someone else with more knowledge regarding the markings will come along....
Perhaps someone else with more knowledge regarding the markings will come along....