So I'm going to back up the guys on the other forum. You need diodes there, and I'd go with the numbers recommended (1N4001 has been mentioned in other forums as a viable replacement for that type, which is called an Epoxy Rectifier Diode).
I'm not perfect, but I do work on electronics for a living (military aircraft) and have worked on plenty of stuff this old.
Also, I'd go ahead and replace all the caps while you are in there. Those are electrolytic caps, and they are usually the first thing to go out on something that age. I'm going to bet that a voltage transient that's usually handled fine by those caps got through and smoked the diodes (which were also degraded).
Actually, I'd just rebuild the whole thing from the ground up if you actually want to use it. This is a dead serious recommendation. You'll get a long life out of it that way. If you were really interested I can talk to you about doing a schematic and etching some replacement boards for people who have these radios. Isn't that hard OR expensive, and it's DIY stuff.