Rear seat belt placement

[Toro]

I have an early 72 Blazer and the back seat has four legs. All the belts are gone, but it looks like the seat belts with the buckle bolts onto the center two legs. On the far left and right side, the belts have been cut off, but I'm guessing this is where the non-buckle part of the belts are supposed to be? How do those attach to the seat? It looks like they go into the fold of the upholstery instead of bolting to legs like the buckles do. I hope my description makes sense, thanks!