It is a fairly ordinary 116bcd three pin ring. You can find NOS rings for $20. NOS on parts that old usually will include some patina. If it does not clean up well do not go to all the trouble of chrome plating. Even if you insist on demonstrable provenance from 1930s and a web pattern very close to what you have now this one should not be difficult to find. Try ebay.fr and ebay.nl.