AbeJr Save yourself some money and do it yourself. If you are handy with hand tools, you and a friend should be able to install 4 D rings in an Hour.
All you need is a drill and a saber saw and wrenchs to tighten bolts.
Very simple install for sure. Make a template if one is not provided. Mark the floor where you want rings. Drill hole to start saber saw. and install bolts with friend under truck to tighten up nuts. Good luck ...Butch
PS would use silicone as a gasket to prevent any water leakage.