Sorry, can't help you a lot there. I don't think I've ever seen one of these. You can try Phil at Mustang II Specialty Shop in Alabama. He is usually the go to guy for most things like this. You can go to Mustangii.net for more info, but here is his contact info:
Mustang II Specialty Shop
90 Glennhaven Road
Phenix City, AL 36869
U.S.A.