No Ninetales is still the same colour as it was before, although it does look like a mixture of Grey and Purple.
Here are Ninetales's Shiny Sprite's in Gen VI, Gen V and Gen IV (HGSS):
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Because Pokémon X and Y is set in 3D it looks like the colour variation is different for each Pokémon even though it isn't... well may be they have gotten slightly lighter or darker. Here are some examples:
Here are Milotic's Shiny Sprite's in Gen VI and Gen V:
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Here are Ho-Oh's Shiny Sprite's in Gen VI and Gen V:
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Here are Venusaur's Shiny Sprite's in Gen VI and Gen V:
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Although Venusaur's stem on it's back is a different colour.
Here are Charizard's Shiny Sprite's in Gen VI and Gen V:
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Hope I helped :)