They are worth what someone is willing to pay for them. The answer may seem a bit vague but that has been my experience with vintage gear. I would search completed listings on the auction site to what they are going for to start with. You might post this on audiokarma as well as some of the DIY forums. Lots of vintage gear heads frequent those sites. That is not to say you won't get helpful answers here but casting a wider net will be advantageous.
Awaiting Ebm's response........
Awaiting Ebm's response........