Dont know if anyone else has asked this, but what do you mean by 'Wig before Pilot'? I thought her hair was the rather blonde/auburn French twist..? Not that awful hairstyle!
The first shots of the pilot that Kate was were with her hair as it was. It was short, and it was down. It was also a brownish-auburn color, kind of light, imho.
But, TPTB thought it wouldn't work, so they reshot everything they had so far shot for the pilot with her in the wig done up as the bun of steel.