I imagine that the original source was speaking of the architectural models built before Epcot Center's construction. Several were built, each with progressively more detail.
Sadly, most things built by WDI's model shop are later destroyed. There's simply not enough room to store so many very large models -- imagine a model as large as that for Epcot, but for each of the Disney theme parks around the world and how much space they'd all take.
The models are portable, however. They're built in smaller, manageable sections and can be stored and transported where needed. My understanding is that WDI keeps certain "landmark" models, but I don't know which models or how many that might be.
I wouldn't mind the opportunity to find out, however. I think architectural and concept models are some of the most fascinating works of art created.
