An interesting addenda. There is some debate about the number "21" on the Pennsylvania masonic world war 1 service badge. While Perseverance Lodge is #21 on the rolls of the Grand Lodge of Pennsylvania, these badges were issued to Freemasons across the state who were not members of that lodge. An example in my collection was from a member of a lodge in Philadelphia. They are engraved and dated (mine is from 1937) on the reverse. I do not have a clear explanation for the 21 although I have suspected this may be when it was authorized but that is a case. They are in sterling.
As an unrelated aside, for those interested in Masonic veterans, the Grand Lodge of Pennsylvania published a volume listing all World War 2 veterans. Titled HONOR ROLE: MILITARY AND NAVAL SERVICE WORLD WAR II, FREE AND ACCEPTED MASONS OF PENNSYLVANIA, 1941-1945. The members are listed by lodge and there is no index sadly. However, it does include service information including decorations.