I'd like to know what is inside the folding rear seat back at or near the top edge looking at it from the rear.
Why you ask? Well I'd like to put some eye bolts across the seat back (at the top edge) so's I can sometimes attach tie-downs to keep 'stuff' from sliding around.
I don't like surprises. . . .

 

I've seen people bolt on head rests on the back seat before, so I'm sure you could put those tie-down points on the seat where people have put the head rest bolts.

 

I placed 6 eye-bolts in cargo area. Using fender washers and placing them where metal is double or triple thickness. Just had to remove interior panels.
Two are at top of fender wells, just behind seat. Two on floor at rear and two higher up at rear, where brake light is.
If you carry passengers or a child in the back seat, maybe look into a cargo net divider.

 

What I am planning on using is an expansion nut or bolt - you drill a clearance hole - insert the nut/bolt - screw in a bolt, say 1/4-20, it expands the back of the nut tightening up the fastner so's you can remove the bolt and then screw in say a eye-bolt to use with bungee cord or straps or rope or . . . . - The eye bolt can be removed and the 'expansion nut' is left flush with the seat back out of the way.