Hi
I've managed to take a photo of two 1915 badges I have. The one APPEARS to be nickel silver and NOT plated but it might take a bit of "vigourous use" of abrasive to confirm this!
The other seems a tad strange and I would welcome any suggestions. Note that the "nickel" version has a 4-digit number, the other has a higher number much as you would see on any of the other 1,000s that litter websites