DCM QED

Hi, came across a pair of QEDs, which from the outer appearance, in very good condition. Because the rubber cover cannot be removed cannot tell the under the hood condition but Im assuming good also for its age but prepared for  potential issues. So a few questions, any general thoughts on this 40 year old speaker? Do you recall if the surrounds are foam or rubber, and based on the description what would you consider a very fair and not insulting to the seller price offer? This would be mated to a Yamaha cr 820. Thanks much, Dave