I have a pair of the short jump seats (with lap belts) available. US$200 plus shipping from Seattle. Sorry, no pics available.
They are in good, serviceable condition. Not perfect, but in good shape. The only defects are:
*one short (3/4 inch?) cut on the vinyl at the corner of one of the seats;
*the canvas web strap for holding the seat in the folded position is missing on one of the seats (I used a bungy cord instead);
*on one of the seats the stamped-steel mounting bracket to the body tub of the truck broke off - a thicker piece of mild steel has been welded on as a replacement. You will need to drill a hole through this piece to mount the seat to the body tub.