The first version of this model was around in the 1960s and was discontinued sometime in the 1970s.
He was a bit of a grumpy looking pony. Fortunately, the second version was a much more agreeable specimen !
The second version was introduced in 1984. My one (above) doesn't have a date letter in his mouth, but he is from the 1980s - he must have slipped out of the workshop unnoticed!
This mould is still available today, just looking a little slimmer.