I went through the same thing with a dual point Mallory distributer about 3years ago, it to was an early type. I contacted Mr Gasket, who I believe now owns Mallory, they are located in Carson City, Nevada, and asked them the same questions that you have. They indicated there weren't many parts available for the early type distributer. I ended up trading in my old one and, if I remember right, only paying $70 to $80 for a new one from them. Unfortunately I didn't ask if they made one with vacuum advance.
Hope this helps
