Hi, Rabbit.
I don't know if they were made of lead. I believe that it was some type of zinc derivative.
Lead and coppper (copper clad the lead ... bullets y'know) were in great need, during WWII.
When WWIII comes about ... it'll probably be something else.
I had a few of those nickles, as well. I wonder what I ever did with my gummint script that the paymaster's handed out, during the duration, over in the Japans.