Pettibone wrote on her blog that she didn't know Chan was wearing one of her most popular creations until she saw one of the photos released from Saturday's surprise ceremony.
Pettibone's publicist said Tuesday that based on a review of sales records, the designer believes Chan used a different last name to buy the dress with an Italian lace overlay at a Denver bridal shop in October. It sells for $4,700.
Facebook representatives didn't return emails seeking confirmation.
The owner of the Little White Dress Bridal Shop, Cate Malone, tells KMGH-TV (http://bit.ly/JNGvWw ) that Chan returned to the store to buy accessories in April and that she didn't know who Chan was.
Designer Claire Pettibone's blog, http://clairepettibone.com/blog/Suggest a correction