I don't have an Optemus, I have a Durst 605 and my ceramic female socket looks much more beige in colour but both my holders, the new one and the old suffering from arcing inside it looked the same on the outside . It is the inside that needs to be pristine and this is the part you cannot see. The seller might be able to tell you when he last changed the ceramic holder but it seems that he/she is no longer answering your inquiries so I'd be inclined to assume worse and assume he/she hasn't replaced the holder for maybe a long time
It's your choice of course but I'd opt to get a new holder if it were me
pentaxuser