Small update. The USSVI vet that I have been talking to said that the display that they have at the Point Loma base are two 5" sub guns and a torpedo. He liked the idea of swapping a 3" gun for a 5" gun to give their display more variety. I think that we're getting the better deal. In the end, we'll just be paying for the shipping costs, which won't be cheap for a 7-ton gun... plus, crating. They can pay for the 3" gun to be shipped to them - or however it works out.
Anyway, he knows the base CO, base CMC (CoB), and the SUBVETS WWII president and he's very interested in pushing this idea to these gentlemen. I detected some real enthusiasm from him in the last email. So, cross your fingers.