Catalogue production was a bane of Citadel's business life, and being given the job of producing them was a bit of a poisoned chalice, as you couldn't keep up with the sheer pace of production.
Remember, this was pre-digital and pre-internet, so by the time you'd finished photographing, getting the shots developed, and then laying out one range, chances are it'd have been added to and so the catalogue pages for that range were then out of date before the catalogue was even published! Mail order flyers were put out to showcase new stuff that wasn't catalogued properly yet, but that only worked if you already purchased from mail order.
This then happened for most current ranges at the time, leading to models that were just missed out from catalogues. They tried to rectify this by turning the back of WD into a catalogue updating mechanism, trying to photo everything as it was released, but that was only from the early 90's onwards.
Another 'feature' of mail order was that regular customers would phone up and just ask 'what's new?'. Mail Order would get stock bins of new castings to see, and se we'd then tell them, and they'd order whatever they were interested in. Some of that stuff never ended up on general release, or was withdrawn for whatever reason, but it legitimately got out into the world via sales.
In short, cataloguing was chaotic and an afterthought to a large degree.