The Marchal light was replaced by the Lucas Square 8 lamp. The Square 8 was a very popular fog light. The correct lens is fluted all the way across and says "ENGLAND" on the bottom. Several close variations have been available over the years.
The most notable versions are a lens that says "Foreign Glass" and one that says, "Made in England" on the bottom. The version shown below is the correct production version. The other versions came after Shelby production ended.
Also make sure the wiring has a small black grommet in the bottom of the housing, not a gray one.
1969 lamps are same, however the lenses were flipped upside down for under the bumper mounting
Dont get taken by the flim-flammers 😉
(http://www.thecoralsnake.com/lucasbp.jpg)