I have recently inherited what looks like a Shure 55AV. To my surprise it is still working fine. The only problem I have is the connector is the type with three binding posts. which does me no good if I want to put it on a stand. Do you carry the XLR/mic stand adaptor so I can essentially make it into a 55A?
Unfortunately all such parts are long gone at Shure.
You might have luck with collectors of old mics. We suggest you start with Tom Ellis: email@example.com