Are you looking for the rubber insert or the aluminum extrution that screws to the gunwale? There is some rubber insert listed on Flebay, if it is the aluminum piece you will probably have to by another Starcraft boat and steal it off of it.
That's going to be hard to find.
You might check some of the scrap dealers to see if an old starcraft shows up.
I have seen some old tin boats in there when dumping scrap metal.
CL Comox Valley has a nova but he want's 3K for it so that would be an expensive path.
I'll keep my eye out as I live in your neck of the woods.
yowsuh! that's the way to bottom feed. park your SC under someone else's 28' Bertram and see what falls off that you can use.....