The silver "stripes" on the sides were supposed to replicate duct tape used to close the gaps on the doors, due to the anticipated and ultimate rain during the event. Since the AutoArt mold is incorrect with respect to the shape of the doors, they put the "tape" on the body work, in lieu of covering the door seams.

https://www.motorsportimages.com/photo/1969-watkins-glen-6-hours-1013741186/1013741186/

https://www.motorsportimages.com/photo/1969-watkins-glen-6-hours-1013741190/1013741190/?p=6&search=Jo%20Siffert%201969

https://www.pinterest.com/pin/533746993319243208/

I created a corrected version for my collection but can't seem to be able to post pictures here.