There was no bed on it when I got it. A 'J' bolt hooks in a hole in the frame then goes through a hole in a tab on the side of the bed rails.
These are on the outside of the truck frame as opposed to "clamping" both sides of the frame with U-bolts or flat plates. This eliminates squeezing the frame on the inside.
Anyway, since my first post, I went with the "J" bolts. Looks good and seems to be very secure. I have driven it over rough ground and nothing has moved at all.
