I did go back to the Huntsman, and the same XC notation is used in the Evil Queens collection as the Queen of Hearts. I also noted the flower pattern in the door is the same for the door in the EQ’s castle to the heart boxes, to the door of her Father’s crypt in Storybrooke, to the structure in Wonderland belonging to the Queen of Hearts. To me Henry’s crypt looks very much like the building in Wonderland. Does the timeline account for Regina’s ability to steal or win these boxes from the Queen of Hearts? The reason I’m thinking they are the same as the Queen of Hearts is when Regina first put’s what she thinks is Snow White’s heart in the box and holds it up, at first she is surprised and questions herself that it’s supposed to open. It is then she realizes the Huntsman has tricked her. So it doesn’t look like she created the vault of hearts. I may be reading too much into it.