Brilliant. Definitely a question first for your friend Max and based on that Mr Urban.
I cannot be 100% certain but from the drawings it appears that the rectangular cross section vase, the subject of this thread, is indeed 617/140.
In Max's collection image there appear to be two small vase sizes, one square (as are both medium and large sizes) and one rectangular, can Max confirm this as Anik thinks they are the same shape.
If there are two shapes for the small size can you ask Mr Urbanm how was this dealt with for pattern numbering? The drawings are not easy to read the dimensions and the answer may be in thise drawings!