That happens more often than you would expect. Brochures are from marketing and show what the manufacturer intends to offer. This gets worked out usually a year or more ahead as the marketing guys have their meetings with dealers.
Once the manufacturer gets into production, and the dealers find out what is actually selling, and what the competition is offering, production can change. Models that aren't selling get dropped, new models that can be built with existing tooling get designed and produced. Dealers get the model information and may have specification sheets to hand out, but new brochures don't get published, the folks who do that are working on next year's sales material.
It would seem that the manufacturer's web site should keep up, but that too requires some work by the marketing folks who are already busy with next year.
Tom Test
Itasca Spirit 29B