Not sure what it is from really, looks old and apparently it was dragged out a barn in this condition. I can believe it. The vinyl is all coming away from the seat base where the glue has lost its grip but this is easily sorted. Widest point is about 10-11 inches and in total it is about 24 inches long, probably fit on a whole heap of frames with a little bracket fabrication.
Fiberglass needs a small amount of repair, there is a small crack down one side, nothing a thin layer of fresh glass cant fix though. Oh and a whole load of resin.
Not entirely decided what the new seat will look like, might not go for covering it all with the vinyl but will decide that after seeing the state of the fiberglass of the hump. Good time for suggestions on styles, and what it might be from!!