[bouncytruck]

does your rear seat have four bracket in the back or 2. There were two different versions. Mine has two and the two center holes in the bed accept seat belt bolts. The outside two bolt the bracket to the bed.

I'm going by memory here because it is dark and cold outside. I believe the front is a 5/8 head with course thread. It's about 1 inch long. The back is 13/16 course thread, both the seat belt bolt (which have an extra long unthreaded portion to the shaft so the belts can swivel on them) and the other bolts too. They are about 1.25 - 1.5 inches long.

If you can wait til the weekend, I might have time to pull one of each and measure, but hopefully someone else already has theirs out to measure.