I read about some of the things that have been made from soybeans a few years back (probably waiting for a dentist), and there was a reference to "wartime exigencies". They should have listed this kind of thing. That's a very neat little collection.
Illinois and Indiana are full of WWII collectors, so you might part with one if it seems okay with the giver of the gift. A ceremonial knife sold for over a half million a few years back.
Nope I just checked and it looks like they are selling for $30. You'll have them for decoration and great slotcar story for another 70 years, I guess.