The plate that you see has a 90 degree bend, upwards I think, so from the side it would look kind of like this
The vertical piece lays against the transom. There are two bolts that extend from the inside of the boat, through the plate, then the transom, then a plastic plate and then through the lower gudgeon, where washers and nuts secure the assembly.
It's different on the Model 2. On my 1989, there is a single rear hiking strap that attaches at a point on the centerline of the transom. When I ordered new hiking straps from Catalina, I got four pieces, two that matched my setup in the front, but neither of the other two was quite right for the back. I called them and asked what was up, and they said all they now made was for the current Model 3 set up and I'd have to modify the straps to work in the rear.
Well Ed, now I'm even more confused about why there are four pieces in my new hiking strap set. I'll have to get them back out (I put off installing them until I got more info or feedback), but the lady at Catalina (when I called to see if the correct set had been sent because I didn't need four pieces) said that was it was the right set as the only set now sold was for Model 3's, and I'd just have to modify. Hmmmm. Is the strap from the barney post to the transom in two parts by any chance on newer models? I'm sure I can work something out, but I don't want to make it look stupid or do something that won't function properly.