The illustrations catalog I have does not show the soft trim(I’ll show its cover) of the back seats of the Victoria models. In there are where these parts are shown, a reference is made to Soft Trim catalog #7515.
If some one here has this catalog they can look it if for you. I do not have one.
I did a search on a a 55 Victoria for sale on you tube. It’s turquoise and White if you find it. About 3/4 the way thru it shows the rear seat. It has the “notches” cut out for the arm rests like the 56. Since the tops were a different design they might be different but it sure looks like the on in my 56 Victoria,
56 Vic, B'Ville 200 MPH Club Member, So Cal.