Hi Jeff, those numbers look fine, in my book 1957-59 run from 220000 to 490000, so you look ok there. That insert sticks out like the dogs whatsits, I am sure you can do better, important to get the right period one. The crystal could be rubed back with a very fine paper then finished off with brasso thats what I did to mine, which as can be seen was very rough, nice to keep original if possible. All that is really needed then is to find a good watchmaker to service it and replace the crown, no big deal really. And of course, dont touch the dial or hands, thats one hell of a rare beast.
