There are known to be some versions of this pony with No Country of Manufacture on the hooves. These may have been available in Spain but may also have been around in other places. Whether the MOC example above is Made in Spain I cannot tell. I do know that the UK carded example has sun-faded and thus her pink hair is not as dark as it should be.

There is also a minor ribbon colour variation on the two Mint on Card European ponies shown above - although the UK card has faded, the ribbon is a much bolder yellow than in the Spanish carded release. Whether this is coincidental or not is unclear.
Singing Pocket can be sold with fading pink and blue hair, and non-fading pink with dark purple hair. There is also a middle version of this which includes a rougher semi-fading pink which can become easily tangled or frizzy (the pony at the top of the page has this type of hair). This hair doesn't necessarily fade in sunlight - but just with time. The hair can also become more brittle.

Mine has not been in the sun at all for the last fifteen or twenty years, but this is how she used to look:
The texture of the hair can be important, as hair can be silky or curlyfrizzy. But the really stand-out differences are the dark blue or dark purple hair versions. Blue is more common in North America, dark purple in the UK and Europe.