I recently found out (and a big thank you to James for finding it) that the costume was used again some years later by character actress Florence Auer in the 1949 MGM film "That Forsyte Woman" where she played Ann Forsyte Heyman. It actually gets more screen time in this film than it did in 'Gaslight". I believe that the costume appears in another film as well around that time. It is amazing to see how many times that costumes were reused! Here is are two pictures of Ms Auer in costume.
Thanks again James for your sharp eye in finding it for me!!