1980 Driver Seat Slider

When we bought the boat I noticed that the spotter seat brackets (Hinges) were loose as were the Driver Seat Slider Base. Thought it would just be a matter of tightening the screws holding them. That worked for the spotters bench, but on the slider track for the Driver Seat, they appear to be bolts and no screws. I can not seem to find where I would access the nuts without pulling out the carpet. If they are not bolts, just crazy long screws, what are they fastening down into?? And I don't really need the slider base, has anyone just pulled that out and put in a solid base??