No, you're eyes are not deceiving you. It appears Kate's dress is identical to the pale pink Emilia Wickstead 'Alice' coatdress the Duchess wore for The Queen's Sovereign's Luncheon and The Queen's Garden Party in May 2012. Kate obviously loved the garment and ordered another one from Ms. Wickstead. It's also entirely possible the pink one was dyed. (Now that's thrifty).