Used wire wheels are not that hard to locate for a 1931.
I agree. Its just that the one that is missing the spoke is totally rust free. I have 6 other wheels, but they are rusty and the effort to clean them up seems like it would be more that finding another spoke.
If everything else is ok on the wheel then I would just look for a scrap wheel to get a spoke. I would be curious why one is missing.
I had honestly not thought of sacrificing a wheel, but I have several that that might be the best use for them.