Of 34 floorplans on the Keystone Passport website page, 16 are "stock only" (being discontinued) and 13 are "new" (introductory phase in models). It appears that only 5 models are being carried forward.
https://www.keystonerv.com/travel-tr...t/floorplans/#
Keystone usually begins the model year in March of the preceeding year (2019 models introduced in 2018 and 2020 models introduced in 2019). They announce discontinued models throughout the production run. Realistically, right now is the "shutdown/changeover" time frame for the 2020 models which will begin appearing on dealer lots in about 60-90 days.
If a dealership ordered or was "force shipped" several trailers, their inventory might reflect several discontinued models while a nearby dealership may not have any of that floorplan based on previous customer sales and/or inventory orders that they failed to anticipate a need or simply not wanting to have excess inventory on the lot. Remember, all dealerships usually buy inventory from the factory, so your dealership is probably paying interest on the "pack loan" he has negotiated with his bank. Depending on his credit limit and his desire to keep inventory on his lot, he may not have anticipated the demand for that model. So goes the inventory availability at almost every dealership. it's a "juggling game" of having what sells and paying for what doesn't sell and that changes with the seasons, the customers and the trends in RV buying...
If you can't find what you want at one dealership, he may be able to get it from another dealer, but unlike automobile dealers, there isn't a "dealer network" with agreements to move inventory around, so he may not be able to find you the model you want, you may be forced to go elsewhere for that model or accept what he can get that's similar.