Thanks, guys.
Barry - to answer your question - I didn't build that rear bench seat. I bought it way back in the winter of 2003, which was the first year I owned the boat. I got it through an online store that I believe was BoatUS. I know the store was a competitor to West Marine, and that West Marine later bought it and shut it down.
I remember that the seat was featured as a replacement for a tuna tower setup on a large sportfisherman. However, the dimensions were perfect for what I wanted. I installed it with just two stainless clamps that I fastened through the deck into the stringers below. They're both on the inside of the seat frame; one on the front port side, and one on the rear starboard side. The horizontal surface is hinged, and lifts forward from the stern.
It has huge storage below. I installed another 18 gallon gas tank in that space, and I also store 8 stainless removable rod holders, a gallon of oil, two life preservers, and soap and brushes there. I think that was one of the best improvements I made to the boat.
Unfortunately I don't have a photo of that setup, and the boat's now stored for the winter. I'll post one in the spring.