For me the best way to tell is to look at the top arrow feathers.
On the 1878's, 1879's rev of 78 and the 1921 the top arrow feathers
go straight back.
All other years, the top arrow feathers angle up.
On the 1878's, 1879's rev of 78 and the 1921 the top arrow feathers
go straight back.
All other years, the top arrow feathers angle up.






















