I too have wondered the same thing. They seem to be stripped down to just a display, but a lot of cool trucks start that way. The ones that I have seen have good bodies and most of the interiors, etc. It makes you wonder what will happen to them, I imagine they will go to the crusher unless someone happens to come in at the right time. They have been fixtures at Old Navy since they opened so if you ever hear of them going out of business then you better run down and ask for the truck. You might also call their HQ and see what they say about the old trucks.
Kyle