At first I thought that was Rarity, but that would be ridiculous. I mean, can you imagine if they did something like use Rainbow Dash’s mold for Fluttershy? That would be totally lazy.
Bit weird they decided to go with a 5-point star. Fits Trixie and Twilight Velvet well enough, but Twilight’s mark uses 6-point stars, and she’s kind of the star of the show.
Most likely just laziness.