Silver Plated or Silver Gilt?

[fyrffytr1]

I am trying to help a friend with an Air Force button he found. We have identified it but have one question. How do we tell the difference between a gilt button and a silver plated one? I thought gilt referred to gold but that is not the case.The button in question's description said it was gilt from 1947-49 and silver plated from 1949 -present day.

 

[SusanMN]

Wiki says that silver gilt is silver with a thin layer of gold, so I think it may have been gold colored.