Apologies. In attempting to find an image to illustrate what I was trying to say, I inadvertantly selected a K-type. However, in my defence, it wasn't one with matchboard sides but one which had been plated over (ironically to make them look more like the all-steel K-types).
Many kitchen cars had their interiors rearranged later in life and externally this showed in the kitchen window modification. I cannot find anything to say when this was done for Joan but there are photographs showing original and modified styles. Some other all-steel K-types (Belinda, Nylar, Phyllis and Thelma)had this modification done in 1947. There are photographs of sister cars of Joan showing the modified windows in 1962 and 1967. Although cannot find a clear statement of when Joan was modified it looks like she was reliveried around 1962 which suggests that you may be correct and that Hornby's 1960s livery should also have a modified window.
As a contrast to this, the model of Loraine correctly has an unmodified window and earlier style crest, so that looks correct for the 1930s.
If you are looking for an all-steel K-type kitchen car in 1960s livery then at the moment I'd say Hornby haven't made a correct one and you'd either have to modify the window or just accept the error. (I am aware of the danger of making this kind of statement though. Pullman information seems to be very patchy.) So I agree with your #202 post.
What period and region are you modelling? It may still be possible to put together a correct rake from Hornby's offerings.