I think that if the cups were intended to be replaced or repaired, they would be pressed in rather then part of the pedal body. I would suspect that if you found a set of restored pedals on Ebay the cones might be new, the bearings might be new, the cups are unlikely to be replaced or repaired, unless they are press fit. You could potentially mill or drill out the cup and press or braze one in as the cup location looks to be supported by the cage, the question is, whether a cup that could be pressed or brazed in would be available. Then you need to replace the chrome, chrome is a very hazardous process that uses toxic materials, so it's likely to be very expensive. I could see repairing those pedals costing over $100 per pedal and they still might not work 100%.

There are some modern pedals that are reproductions of older designs, any rat-trap style pedal would be a good option, like these not exactly period correct, but close enough that give them 6 months use, most people would not be able to tell.