Correct me if I am wrong.
But what I know is that you have 3 version: regular, hunchback and dwarf.
The regular version has all 4 hooves stamped, hunchback had 2 hooves stamped liek this (1.©82 Hasbro 2. Italy 3. -4. -) and the dwarf has her hoove stamped like this (1.©82 Hasbro Pat Pend 2. Italy 3. -4. -).
So the dwarf has only 2 hooves stamped and with pat pend.
Also dwarfs are italian ponies
Hope I helpt!