How to remove rear seat belts?

[Dibbons]

Need to remove the outboard rear seat belts in 72 SSP project car. Looks like a couple of rivets or something holding the plastic cover placed over the windup mechanism. How does one remove these belts and the anchors? (need to renew/paint the floor before installing carpet) Thank you.

 

[72 BLUE 400]

there is a seatbelt bolt under neath,its usually covered with seam sealer,you almost have to lay on the floorboard to see it.