Are you sure this is a DS II and not a DS I? The rubrail that you describe sounds more like what was on the DS I (and most of the smaller O'DAYs from the 1960's) The Hull/Deck joint on the DS II sort-of formed the rubrail and what you describe (and maybe I'm just not seeing it right?) does not seem like it would fit the gunwale. It may be that your rubrail was added by a previous owner? I'd give Rudy Nickerson at D&R Marine (508) 644-3001 a call, he sells rubrail that will definitely fit the DS II (I may eventually add this to my DS II). He has the type rubrail that I think you are describing as well. My old 1969 Widgeon had a rubrail that matched your description, it was a rubber or vinyl molding that fit over a T-shape (actually "Pi" shape) plastic molding that was fastened to the hull-deck joint. Hamilton Marine in Maine (they have a website) also carries this type of rubrail.