In her promotional stock images she does indeed look as though she has black at the front of her mane. Whereas in "person" she appears to have a dark grey. In her promotional shots she is also missing the "Hub" sticker and "TRU Collectors" sticker and in person she has these stickers on her box.
You cant trust promo shots
These are often done with prototypes/pre launch products or even mock ups for box artwork rather than a finished product. I think thats the difference you are seeing a promo shot and a real life shot.
As yet we have only seen the CC Zecoras anyway, the TRU Zecoras I dont think have actually been shipped to anyone anywhere.