Martin,
I had to improvise on the door rods from the latch to the inside door handle. Kar makes a set of reproductions, but they use some yellow nylon material and they are about 85.00 for the set. Scott Drake also offers the Kar set. I sent my rods out for silver cad plating and used the insulators. Ford use exactly the insulation I showed you. I contacted Dead Nuts to let them know so they could market it for use on the latch rods, but the guy was less than enthusiastic. You're welcome for ingenious use of your product and another way to market and sell said product..
Anyway, the '67 vehicles use the same product on the wire for the license plate lamp. It comes with a butt splice because to change the insulator you would have to cut the wire. It's a metal tube style, not the typical plastic butt splice. You'll have to cut the wire and do the same if you choose to change the insulation.
-Keith