KD stamp on tulip chair  

Hello, I have two Tulip chairs and I understand the BR 50 and BR 51 stamps were not used after approximately 1969. I have two chairs stamped KD. I have seen others ask the question about this stamp but have never seen an answer. Is this a stamp that was used by Knoll on the Saarinen tulip chairs. Since the chairs were manufactured in various countries does this stamp indicate that it was made outside of North America?? Or is this the stamp of a replica. The chairs were purchased somewhere between 1970 and 1972 originally. Thanks for your help.