Hi Tim,
Don't know if the originals were metal or plastic on some models but I got mine off a German mob called Motomobil, you can find them on the net. I ended up with the estate ones which are longer but can be trimmed to size. They are good quality chromed plastic ones and come in a roll, in original Ford wrapping. Tried some imported reproduction ones but they were flimsy and silver in colour. Prices were reasonable and good service.
One of the van boys on the forum found some nice looking after market general ones which he trimmed to size and glued on?? ...
Cheers,
Len