https://en.numista.com/catalogue/pieces546.html
Personnally I think this is clearer, than the existing documentation:
In 1973 two types are known.
Obverse:
Die 1 - wider portrait, thiner symbols.
Die 2 - narrower portrait, thicker symbols.
It is easy to distinguish them by diacritic symbols of rough breathing in front of first letter and grave over 'H' in 'ΕλλΗΝωΝ'. In Die 1 the rough breathing is small and grave is small and high. In Die 2 the rough breathing is large and grave is large and inside the letter.
Ole