Triumph Bonneville 1959

I have a new Triumph Bonneville that I am modifying to look more like an early 60s model. I am looking for a source for the metal trim that runs horizontally on each side of the Triumph Classic tank badge (also called the harmonica or mouth organ-style tank badge) found on late 50s and early 60s Triumphs.

Does anyone have a source for such trim, or know of an authentic-looking reproduction? Here is a photo of a 1959 Bonneville showing the trim.