Perhaps they are a one time use
I think you're right. I started turning the nut on a bolt and it got tight fast so I stopped since I was just checking. I'll plan to use it once.
How do you plan on keeping the drawers closed when driving?
The draw slides are for the sofa-bed. If you look at the top photo on this page you can see the sofa-bed with the electric actuator in the center. The actuator is what will open (open position bed) and close (closed position sofa) the sofa-bed.
You can see angled metal on the 30x31 inch plywood end. Originally the bed was supposed to slide on this. Didn't work as well in practice as in theory. The draw slides will replace the metal angle.
My bed will run along the wall behind the drivers seat. My floor plan is to have a clear center aisle so I can still use the van for occasional hauling. One reason for the electric part is the lack of room for muscling it open since there will be cabinets across the aisle from it. Once it's bolted into place I'm not planning on moving it.
A nice thing about the movable mattress is to lift it off the platform after a cold night, and let all the condensation evaporate, otherwise mildew will form.
Good to know. I hadn't thought about that.