Hi, does anyone know when Otto Jos Klier started engraving their logo on the button of their cellos? I'm looking at an OJK 504 cello made in 2000 without a logo. I understand that the company was taken over by another owner from 2002. The information I have indicate that cello nos. 10 and above produced from that time have the logos on them. I have no knowledge whether cellos made before 2002 have logos put on the button. Appreciate if anyone knows of OJK's history with regard to placing their logo on their instruments.

Thanks very much!