I just stumbled over this site that sells Kelly Gang thimbles:
From the site:
"The 'Kelly Gang' Collectible Thimble series adds another layer to the mythology of the Kelly gang and is a must-have for any Australian thimble collector.
The Kelly Gang thimbles are made in Australia from high grade pewter. They have an authentic aged patina and are hand finished. There are four unique thimbles in the series, depicting the four unique helmets worn in the Glenrowan siege by the Kelly Gang. Each has its own unique features. The detail in each thimble is extraordinary, right down to the nuts that held them together."
The site goes on to show each thimble and gives a short description of each. One of the things that was interesting was where it said of the small slit in Joe Byrne's helmet that "Joe was reputed to have been afraid of being hit in the eyes by a shotgun blast." I had read at another Kelly site where a visitor to the Not Just Ned exhibition in Canberra told of a tour guide saying basically the same thing regarding Joe's helmet. I wonder what the original source is for that information?