Not sure what I'm looking at. I know what it is on my 2007, but can't picture it from your pic. I think it may be the piece that slides down into a fitting in the fiberglass. You should be able to take it out and have a duplicate made out of stainless by any good machine/welding shop. I have very infrequently seen the entire seatback on ebay, I think at Rusty-Rons Marine Surplus. I have replaced some of my more worn bolsters and cushions by browsing ebay. Few good deals though.
