I have removed those nuts before. They remained tight, But I then tried to reuse them and they did not work as designed. The star would spin on the bolt. Perhaps they are a one time use or different design.
Nice drawer slides.
How do you plan on keeping the drawers closed when driving?
My bed lift requires muscle to attach it to a center adjustable height S hook. and underneath I built two Birch plywood boxes that fit tightly in between the storage areas I built over each wheel humps. I then Use a 1 foot 5/8 inch thick long white oak wedge to press the 2 storage boxes into the wheel well storage. I used a lot of felt padding on the bottom of the boxes to allow them to slide easily, But they are pretty heavy filled as I have them, and muscle is again required.
Crude but effective, and maximizes underbed storage. I can also remove the mattress, bed platform, and storage boxes in under 5 minutes. I can store them to the side and be able to load 4x8 sheets of plywood inside. Again, crude but functional.
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.