I see photos of the 18' Chieftans with bow rails, and photos of them without. Mine doesn't have one, and there are no mount holes, on the deck, so I'm guessing she never did. Mine is a 1978. Were those an add-on accessory, from the factory? I see some that are just curved low rails, that don't go all of the way around the bow, and some that are higher profile, that DO go all of the way around the bow. The latter, is what I would like to have, for mine. Anybody know about these?